Patent Publication Number: US-2005131805-A1

Title: Software interface, method and computer program product product for linking a business application to a component of a computer-based transaction tax processing system

Description:
FIELD OF THE INVENTION  
      The present invention relates generally to transaction tax processing, and more particularly to software interfaces for linking a business application to a component of a computer-based transaction tax processing system.  
     BACKGROUND OF THE INVENTION  
      Besides an income tax system which imposes income-related tax liabilities on individuals and corporations, most countries have a transaction tax system. A transaction tax liability is induced by an individual commercial transaction, such as the sale of a good, the purchase of a service or the like. Typically, the transaction tax is a certain percentage of the price of the good or service. Normally, the transaction tax is collected by the vendor or service provider, who pays the accumulated transaction tax at certain time intervals (e.g. monthly) to a tax authority (for the sake of simplicity, the following description only mentions the purchase of goods, but is likewise directed to the provision of services etc.).  
      Throughout the world, there are mainly two different transaction tax systems: sales and use tax and value added tax (VAT). In a sales and use tax system, which is imposed in most states throughout the United States, the tax amount is derived by applying the tax rate to the retail sales price of tangible personal property or certain enumerated services. If a product is manufactured and sold in a supply chain, all transactions are non-taxable re-sales until a final retail sale to an end-user, which is taxable unless the end-user can claim an exemption from the tax. Thus, in a sales and use tax system, no tax is applied to a product until sold at retail. In a value added tax system, which is applied in many European countries, in a supply chain the transaction tax in a single individual step corresponds only to a percentage of the value added in this step, i.e. to the difference between the amount of money the vendor receives for the sold product and the taxable amount he had to spend in order to manufacture or provide the good. In such a value added tax system, the amount of transition tax accumulated over all the steps of the supply chain is independent of the number of transactions in the chain, it only depends on the price of the finished product. However, normally the “added value” is not determined in individual transactions. Rather, every vendor accumulates, on the one hand, the tax received from buyers and, on the other hand, the tax he has paid to other vendors for all the transactions occurring within certain time periods (e.g. months) and pays only the difference between these two accumulated values to the tax authority. Therefore, also in a value added tax system, when looking at an individual transaction, the buyer has to pay a certain percentage of the product&#39;s price to the vendor.  
      Besides these principal differences between sales and use tax and value added tax, the transaction tax regulations vary from country to country, and, in the United States, even from state to state down to the level of cities and areas. For example, there are different rates in different countries and even in different states. In addition, the tax rate may depend in a country or state specific way on the seat of the vendor and/or the buyer and/or the origin and/or the destination of the good when it is shipped from the vendor to the buyer. In many countries there is a tax rate of zero for exported goods. However, in trade within the European Community transaction tax has to be paid in the country where the transaction takes place, but is then credited to the destination country in a clearing procedure carried out by the tax authorities. Also the requirements for transaction tax related bookkeeping, reporting and the form and period of tax declarations to the tax authorities generally vary from country to country.  
      In view of the ever-growing internationalization and globalization of enterprises and trade, there is a need for computerized systems which enable enterprises to fulfill the transaction tax requirements (preferably for different countries and states) in an efficient way.  
      Several products of this kind are already on the market. In one type of product, an enterprise resource planning (ERP) application (which traditionally provides for accounting, manufacturing logistics, supply-chain management, sales-force automation, customer service and support, human resources management, etc.) also enables the user to deal with the transaction taxes. For example, the ERP product R/3 by SAP provides a facility for transition tax calculation for different European countries, but not for the United States. Another type of product is a specialized application for transaction tax calculation and reporting. Examples of such an application are “TaxWare”, “Sabrix”, “Vertex” and “Datev”.  
      Moreover, U.S. Pat. No. 6,078,899 discloses a point of sale tax reporting and automatic collection system. U.S. Pat. No. 6,298,333 discloses a computer system and method which provides a solution for a particular transaction tax related problem, namely the determination of correct use tax on moveable equipment for leasing companies.  
     SUMMARY OF THE INVENTION  
      The invention provides a software interface for linking a business application to a component of a computer-based transaction tax processing system. The interface enables the exchange of commercial-transaction-related data, providing a mapping of the data between the business application and the component of the computer-based transaction tax processing system. The mapping is configurable via user-defined rules.  
      According to another aspect, the invention provides a method for mapping data between a business application and a component of a computer-based transaction tax processing system. The data are related to a commercial transaction. The mapping is configurable via user-defined rules.  
      According to still another aspect, the invention provides a computer program product including program code for carrying out a method for mapping data between a business application and a component of a computer-based transaction tax processing system, when executed on a computer system. The data are related to a commercial transaction. The mapping is configurable via user-defined rules. 
    
    
     DESCRIPTION OF THE DRAWINGS  
      In the accompanying drawings:  
       FIG. 1  shows the main components of the transaction tax processing system;  
       FIG. 2  schematically depicts the delocalization of the major components of the transaction tax processing system and its connections to each other,  
       FIG. 3  illustrates the various processes performed by the transaction tax processing system;  
       FIG. 4  shows an example for the processes executed during a transaction tax calculation and a transaction tax logging;  
       FIG. 5   a  shows a simplified diagram of an interface used between an external application and a transaction taxation processing service;  
       FIG. 5   b  shows an exemplary flowchart of an external sales order module invoking a transaction taxation processing service;  
       FIG. 5   c  shows an exemplary flowchart of the interface shown in  FIG. 5   a;    
       FIG. 5   d  illustrates the flowchart shown in  FIG. 5   c  in more detail;  
       FIG. 5   e  shows a simplified diagram of a more complex business application communicating with the transaction taxation processing services via a standardized data model;  
       FIG. 6  shows three tables “Inbound Data elements”, “Outbound Data elements” and “Further processing elements” listing different data elements of the standardized data model according to a preferred embodiment of the invention;  
       FIG. 7  is a flow chart of a method carried out by a transition tax logging service;  
       FIG. 8  is a diagram of the functional architecture of a transition tax filing service.  
       FIG. 9  shows an exemplary flow chart of an auto-completion module according to a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      In  FIG. 1  the main components and architectural layers of the transaction tax processing system are depicted. Before proceeding further with the description, however, a few items will be discussed.  
      In the preferred embodiments a software interface is provided for combining a business application with a component of a computer-based transaction tax processing system. The interface enables the exchange of data that is related to a commercial transaction. The interface provides a mapping of the data between the business application and the component of the computer-based transaction tax processing system, wherein the mapping is configurable via user-defined rules.  
      Examples for commercial transactions that may be subject to a transaction taxation are orders, financial credits, quotations and bids, incoming or outgoing invoices, returns and credits, or internal financial transactions between business units of the same company belonging to different legal or taxation systems. Data that are related to such commercial transaction are for example the price of a product or a service, a shipping address, the customer address, a product name, the purchase date, etc. These data are usually created, processed and/or stored in a business application and have to be transferred to a computer-based transaction tax processing system for further processing. In the course of this data exchange, a mapping of the data between the business application and the component of the computer-based transaction tax processing system is required. In the preferred embodiments, this mapping is not hard-coded and thus very flexible. The term hard-coded means that the mapping functions are encoded in the mapping software module, compiled and integrated into the software interface. Changing the existing mapping function or adding new rules to the mapping functions would therefore require additional coding, compilation of the code and linking and integrating it into the software interface each time the mapping function has to be changed. In the preferred embodiments the mapping function can be configured by a user via rules, having the advantage of allowing a flexible change and adaptation of the mapping function without coding, compiling and linking. Thus an easy way is provided to the user for adapting the mapping to new requirements.  
      In the preferred embodiments, the computer-based transaction tax processing system comprises at least one of the following basic service modules: A transaction tax calculation service, a transaction tax logging service, a transaction tax content service, a transaction tax compliance service, a transaction tax filing service and a transaction tax database for storing selected information which is related to transaction events. These service modules provide the basic functionality of a transaction tax processing system. These services are services in the sense of a software module or component providing a specific functionality to the overall transaction tax processing system. However, the transaction tax processing system of the preferred embodiments may only comprise a part of the above service modules, or even only one of the above service modules.  
      In the preferred embodiments, the transaction tax content service is the database containing the specific jurisdiction and rules for the various countries as well as the various tax rates and other information needed to comply with the country-specific requirements. The transaction tax calculation service provides the basic functionality of calculating the transaction tax for a specific transaction. The transactions tax logging service decides which transactions and which content of the transactions should be logged for further reporting, that is which kind of data are needed for further analysis, auditing or reporting. The transaction tax compliance service automatically processes the logged information in a way which is suitable for a consecutive auditing. The transaction tax filing service finally is able to automatically fill out the appropriate tax forms and reports and file it electronically to the appropriate tax authority. The transaction tax database finally stores selected information which is related to transactions and provides this information to further applications such as data mining or data analysis applications.  
      In the preferred embodiments, the mapping is performed using a standardized data model making it easier to adapt the interface to different business applications. Preferably, the mapping comprises the steps of i) mapping from the business application to a standardized data model, and ii) mapping from the standardized data model to the component of the computer-based transaction tax processing system. Using this two-step mapping provides further flexibility in linking different business applications to different components of a computer-based transaction tax processing system. The standardized data model has the function of an “adapter”. Once the mapping of the various business applications to the standardized data model and the mapping from the various components of the transaction tax processing system to the standardized data model is implemented, all possible combinations between those various business applications and components can be realized directly without adapting the direct mapping individually for each combination and thus reducing significantly the maintenance and programming efforts.  
      In the preferred embodiments the computer-based transaction tax processing system comprises one or several basic service modules, preferably according to the ones described above, and those basic service modules further comprise a number of micro service modules. The mapping within the transaction tax processing system is performed preferably by such a micro service module.  
      Advantageously, the interface is based on a Web protocol using preferably the Hypertext Transfer Protocol (HTTP). In this way, the servers hosting the business application and the component of the transaction tax processing system may be distributed within a network and may be separated geographically without any need of adapting the software interface. Most preferably, the data transmitted by the Web protocol are encoded using the Extensible Mark-up Language (XML).  
      The mapping between the parameters of the business application and the component of the computer based transaction tax processing system can either be a one-to-one mapping or a many-to-one mapping in the preferred embodiments. A one-to-one mapping means that to each parameter of the business application exactly one parameter of the component of the transaction tax processing system is assigned. The assignment however, is very flexible due to the configurable mapping function. The specification which parameter of the business application is assigned to which parameter of the component of the transaction tax processing system can be freely defined by the user using a set of rules. On the other hand, in a many-to-one mapping, several parameters of the business application are assigned to one parameter of the component of the transaction tax processing system, or in the case of data transfer in the other direction, several parameters of the component of the transaction tax processing system are assigned to one parameter of the business application. Again, the specification of the individual parameter assignments is flexible and configurable via user-defined rules. In the preferred embodiments, also constant values may be assigned to one or several parameters in either one or the other direction of the mapping, whereas the constant value can be defined by the user.  
      In the preferred embodiments, the user-defined rules are implemented and stored in a look-up table. That means, that the mapping function retrieves its mapping rules from a look-up table in which the user has stored the rules containing the predefined assignments of the parameter sets. Alternatively, the user-defined rules are implemented using a script language which allows the user to specify rules using for example logical or arithmetical operators provided by the script language.  
      In one preferred embodiment, the interface between the business application and the component of the transaction tax processing system is realized as an application programming interface (API). Alternatively, the business application is an Internet portal offering transaction-tax related services. Preferably, the business application is an enterprise resolved planning (ERP) application or, in particular, the product R/3 by SAP. In a preferable case of the preferred embodiments, the component of the computer-based transaction tax processing system is a transaction tax calculation service which may be a part of the transaction tax processing system or may be performed by an external service provider. An example for such a transaction tax calculation service provider is the company TaxWare.  
      The term transaction tax (TT) and transaction taxation, sometimes also referred to as turnover tax, covers all kind of taxes which apply to commercial transaction processes of a company such as sales or purchases. The taxation regulations for those transactions vary from country to country and may even vary from state to state or district to district in one country. Examples for such transaction taxes are the sales and use taxes applied in the United States or the value-added tax used in most European countries.  
      The general requirements for a transaction tax processing system are the capability of calculating the transaction tax taking into account the country-specific requirements for national and transnational transactions, the reporting and storing of the tax-related data for auditors information or company-internal use and the filing of the tax report to the appropriate tax authority.  
      Transactions within a company which might be subject to a transaction taxation comprise orders, financial credits, quotations and bids, incoming or outgoing invoices, returns and credits, or internal financial transactions between business units of the same company belonging to different legal or taxation systems.  
      Usually, the transactions which are subject to transaction taxation are processed within a business application, or more particularly, within an enterprise resource planning (ERP) application such as the product R/3 by SAP. Therefore, the transaction system has to be linked to those business pr ERP applications, i.e. an appropriate interface has to be provided. Alternatively, the execution of the transaction tax processing system may be initiated via the Internet For example, an e-business portal is provided in the Internet offering a service for transaction tax calculation. In the first case, the connection between the business application and the transaction tax processing system is realized as an Application Programming Interface (API), while in the second case the execution of the transaction tax processing system may be triggered by a client request transmitted via Internet using the HTTP protocol. In both cases, there is usually no standardized data model for the exchange of parameters with the transaction tax processing system, i.e. the transaction tax processing system needs to be able to handle various data formats and models.  
      The Hypertext Transfer Protocol (HTTP) is the protocol used in the preferred embodiments for communication between the different software modules of the transaction tax processing system, and in particular, between the basic services and micro services. The HTTP protocol is the standard communication protocol used in the World Wide Web (WWW), which is referred to as the Web. However, other future Web protocols or other versions of the HTTP protocol may be used in the preferred embodiments.  
      Various data types may be used for the exchange of information between different Web servers. In the preferred embodiments, the Extensible Markup Language (XML) is used as Web-based technology for the interface between the different software modules of the transaction tax processing system (that are possibly geographically delocalized) in order to exchange the necessary parameters. This technology allows a flexible design of data models. Each data element of the data model comprises an identifier, which can be freely defined in the so-called Document Type Definition (DTD), and a corresponding value. In contrast to HTML (Hypertext Mark-up Language), in which the data types are restricted to a given set of data types, an XML programmer can define his own data elements according to the specific needs of the application. Typically, in XML a data element is transferred via the Web using the syntax: 
 
&lt;parameter_name id=“id_name”&gt;parameter_value&lt;/parameter_name&gt;
 
      where the data element “parameter_name”, which is sometimes referred to as “tag”, is identified by its ID and carries the value “parameter_value”. In this way, parameters can be passed from one software module of the transaction tax processing system to another via the Web. The data structure of XML documents can be defined by means of a Document Type Definition (DTD) or an “XML-Schema”. The use of XML with an “XML-Schema” as Web-based interface technology for the transaction tax processing system has the advantage of being more flexible in the definition of more complex data structures.  
      The term exchange of data relates to a software interface that transfers data from one application or software module to another. However, the term exchange does not imply a transfer of data in both directions and thus is not restricted thereto, but particularly comprises a transfer of data only in one direction.  
      The term data record relates to an instance or embodiment of a data model e.g. a data set or file transmitted via the Internet, stored on a hard disc, CD, disc, or DVD, etc. Such a record comprises a number of data items corresponding to the data elements of a data model.  
      Now coming back to  FIG. 1 , which depicts the different layers of the architecture of the transaction tax processing system of the preferred embodiments. The application layer  2  comprises the software or the event which initiates the execution of the transaction tax processing system. Basically, there are two possible ways to call the transaction tax processing system. In one of these, a business application program  12 , such as an enterprise resource planning (ERP) application like SAP R/3 or legacy, demands transaction tax (TT) services  20  via an application programming interface (API)  16 . The ERP  12  processes and stores the transaction-related data and passes the relevant parameters over the interaction layer  4 , i.e. the API  16 , to the process and communication layer  6  of the transaction tax processing system. In the second way, a client requests transaction taxation services  20  via a Web portal  18  using the HTTP protocol. Two general embodiments of such a portal are possible. In one embodiment, the portal  18  offers a service via a Web page on which the user may specify certain transaction parameters, e.g. the purchased product, the price, the production location, the shipment location etc., and requests interactively a corresponding transaction tax calculation from the transaction tax processing system. The clients does not need to know anything about the taxation rates, the jurisdiction and regulations in the specific production and shipping countries nor to know about recent changes. The client gets back the accurate tax value and taxation rate for the specified transaction. There is also the possibility for the client to retrieve general information on taxation rates and regulations for various countries using the Web portal  18 .  
      Another way to use the Web portal  18  would be by connecting the Web portal  18  automatically via a HTTP connection to a client application which might be an e-business application requiring some kind of transaction tax calculation. This client e-business application  14  then requests transaction tax calculations from the transaction tax processing system via the portal  18  automatically during its execution.  
      The main functionality of the transaction tax system is implemented via basic services  8  and micro services  10 . A basic service  8  usually aggregates a number of micro services  10 . However, micro services  10  can also be called as stand alone modules.  
      In the process and communication layer  6  specific processes for the specific client requests are defined. For each specific request a certain workflow has to be performed which is controlled by the process and communication layer  6 . It controls the calls of the various basic and micro services  8  and  10  and provides the communication between those services.  
      This layer is based on the HP (Hewlett Packard) e-speak technology which integrates the various basic and micro services. Based on a set of micro services  10  the basic services  8  are used in combination or stand alone within the various process steps of the transaction tax services  20 .  
      The architecture is a true Web-based architecture using Web technology. The communication between the process and communication layer  6  and the basic services  8  as well as the micro services  10  is based on Web technology such as HTTP using XML for exchanging parameters. Moreover, the same Web technology is used for communication between the basic services  8  and between the micro services  10  as well as for communication of these services  8  and  10  with each other. This standardized interface purely using Web technology allows an easy integration of new basic or micro services into the system and a complete delocalization of those basic and micro services without the need to introduce further network communication technology.  
      The transaction tax services  20  comprise and control a number of basic services  8 . The content service  22  is the database containing the specific jurisdiction and rules for the various countries as well as the various tax rates and other information needed to comply with the country-specific requirements. The TT calculation service  24  provides the basic functionality of calculating the transaction tax for a specific transaction. The TT logging service  26  decides which transactions and which content of the transactions should be logged for further reporting, that is which kind of data are needed for further analysis, auditing or reporting. The TT compliance service  28  automatically processes the logged information in a way which is suitable for a consecutive auditing. The TT filing service  30  finally is able to automatically fill out the appropriate tax forms and reports and file it electronically to the appropriate tax authority.  
      In the preferred embodiments these basic services  8  make use of many other micro services  10  such as a service  32  for managing the data base access, a micro service  34  for mapping the data between the data models and formats of the different applications, a micro service  36  for determining the specific jurisdiction, a micro service  38  for retrieving the correct tax rate for a specific transaction, a micro service  40  for carrying out elementary tax related calculations, or a micro service  42  for auto-completing incomplete data sets.  
       FIG. 2  visualizes schematically an example for a possible geographical delocalization of the various services which are part of the TT service  20 . Due to the differences in transaction taxation jurisdiction in the different countries, an international company usually comprises local transaction tax processing systems which are adapted to the specific requirements of a certain country and cannot be integrated in and communicate with the other transaction tax processing systems of the company. In contrast thereto, the preferred embodiments of the transaction tax processing system allows the integration of the local transaction tax systems into one system by using Web technology for the communication between the various software modules. Moreover, a standardized data model is used within all basic services and micro services facilitating the interface between two interacting services. A Web technology used in the preferred embodiments is the HTTP protocol using XML for passing the parameters from one service to the other.  
      In the example shown in  FIG. 2 , a client  102  located in Asia requests the transaction tax service  20  in Europe via the Internet. This TT service  20  controls the required process by calling other basic services such as the calculation service  24 , the content service  22  and the filing service  30  which are located in different countries. Due to the Web-based technology of the communication between the services, the geographical proximity of the services is no longer necessary. Thus, the location of the filing service is located in the country of the appropriate tax authority, the location of the calculation service is chosen according to other criteria like the cheapest hardware infrastructure or the location of a third party provider, while the various content services  104  are distributed geographically across various countries according to the location of the experts in the different countries.  
      In  FIG. 3  the principal process of a transaction tax calculation of the preferred embodiments is schematically depicted. Not all basic services are executed for any calculation request as the exact process varies depending on the specific calculation request  202 . The definition of a specific process and the control of the order of execution of the various services and their communication with each other is performed by the process and communication layer  6  of  FIG. 1 .  
      In the preferred embodiments a calculation request  202 , e.g. from an external business application, initiates the transaction tax calculation. The calculation service  24  then calculates the transaction tax on the basis of the parameters received from the calculation request  202 . For this purpose, the calculation service  24  demands data from the content service  22 , and in particular from its component  212  containing rules and rates and its component  210  containing the master data. The master data  210  is a centralized data base containing for example company information of a registered client, i.e. the company for which the transaction tax is calculated. Such company information for example can be the legal structure of the company which influences the type of tax calculation.  
      In the preferred embodiments, the content services  22  basically has the function of an interface used by tax experts for inputting, defining and maintaining the taxation rules and rates, as well as the logging and filing requirements. In particular, the components  210 ,  212 ,  214 ,  216  and  218  represent not only rules, data and templates, but also configuration interfaces which enable the user to input and configure these rules, data and templates.  
      For the parameter transfer between a calling business application and the transaction tax processing system a standardized interface data model called a tax object (T-object) is used. This standardized tax object allows a flexible link of different business applications to the transaction tax processing system. In one preferred embodiment, the same data model (T-object) is used for the internal data exchange yielding a high degree of modularization and flexibility for the integration of new modules in the existing system. In addition, in the preferred embodiments the rules requested for a specific transaction tax calculation are transmitted from the content service  22  to the calculation service  24  via an additional meta data model.  
      In the preferred embodiment according to  FIG. 3 , the calculation service  24  passes its results to the logging service  26  via a Web-based standardized interface using the T-object data model. The logging service  26  is able to retrieve logging requirements  214  from a specific section of the content service  22 . This service allows the user to define what kind of transactions are to be logged and what data elements are needed as well as automatically recognizing the transactions which have to be logged. The logging requirements reflects tax jurisdictional requirements as well as special regulations of a certain client. They are defined in the form of rules. Thus, the logging service  26  automatically determines the content which has to be logged and writes the result to the data warehouse  204 . In the preferred embodiments, also data from other tax calculation engines and history data  220  can be loaded to the logging service  26 .  
      Like the other communication connections between the basic services and micro services, the interface between the logging service and the data warehouse is realized in XML on a HTTP connection. While the exchange and transfer of internal data within the transaction taxation service and possible to external business applications is based on the T-object data model, the content of the data warehouse  204  is stored using a different data model, a so-called data warehouse data model. Usually, the requirements for these two data models differ for various reasons, for example because of legal or auditors requirements, internal software specific requirements or requirements of other external business applications that work together with these data models. Therefore, these two data models do not have to be necessarily identical. Either some data elements of the data warehouse data model may not be part of the T-object data model, or vice versa. Additionally, the data warehouse data model may be a subset of the T-object data model, or vice versa.  
      The logging service  26  additionally ensures that the logged data satisfy the local authority&#39;s needs. Furthermore, the calling business applications no longer need to know which transactions have to be logged e.g. for the auditor&#39;s report or for which transactions a transaction tax calculation has to be performed, as this is automatically recognized by the logging service. The logging service thus guarantees the availability of all transaction data needed for compliance reporting and tax filing also in the case that the transaction tax has not been calculated within the transaction tax processing system but by an external transaction calculation engine. If data to be logged are incomplete, the logging service can use the auto-completion micro service  42  to ensure that the logged data are complete.  
      The data warehouse  204  represents the database for the compliance reporting and filing service  28 ,  30 .  
      The compliance service  28  retrieves the report content from section  216  of the content service  22  and produces the compliance report for the auditors. If information is missing for the auditor&#39;s report, the compliance service  28  can call the auto-completion micro service  42  to complete such missing information automatically in the preferred embodiments.  
      Similar to the compliance service  28 , the filing service  30  relies-on the transaction data from the data warehouse  204  to fill out the specific tax filing forms required for a certain transaction. As for the compliance reporting, the filing service  30  is able to complete missing information automatically using the auto-completion micro service  42  in the preferred embodiments. The necessary tax filing form templates  218  are defined and stored in the content service  22  and serve as a database for the filing service  30 . Based on meta data from the content service  22 , the filing service  30  determines what transactions need to be filed and creates the respective information needed for the filing. The completed tax forms can then be filed electronically or as hard copy with the local tax authority according to the respective governmental requirements which are as well retrieved from the content service  22 .  
      In the preferred embodiments, an auditors service  208  is provided which retrieves via a Web-based connection technology information from the compliance report and transaction data from the data warehouse  204  in order to provide information for the auditing.  
      The data analysis interface  206  provides an access to the central transaction database contained in the data warehouse  204  for other internal or external tools. Such tools may be data mining or other analysis tools for business relevant formation. It can also be used for tax optimization purposes for example by simulating required transaction taxes for a special supply chain scenario.  
      In  FIGS. 4   a  and  4   b , a concrete example for a transaction tax calculation according to the preferred embodiments is given. This example is a simplified representation of a specific transaction tax service. Usually, a transaction tax service comprises additional and more complex micro services which have been omitted here for the sake comprehensibility.  
      Assuming that a third party orders a book for the price of 40 Euros via the Amazon Web page  302  and pays the price of the book by credit card transmission. In response to this selling event, Amazon requests a transaction tax calculation  304  by a transaction taxation service  20  demanding the calculation of the tax for this specific transaction using the HTTP request  34 . The data related to this specific transaction are passed to the transaction taxation service  20  using XML. In this Web-based technology, a list of parameters  306  for this specific transaction of selling a book comprising for example the parameters invoice number, country, price, product and requested kind of service is transferred encoded in XML to the TT service  20  via a HTTP POST request. For each parameter a XML tag is defined containing the corresponding parameter value.  
      In this specific case the first micro service called by the TT service  20  is the “data mapping”  34  as shown in  FIG. 4   b . The micro service “data mapping”  34  implements the interface between the XML parameter list and the T-object, which is the standardized data model of the TT service  20  by converting in step  316 , the Amazon parameter list into the data elements of the T-object. During this mapping it might occur that there is no one-to-one mapping between both parameter sets so that some logic has to be applied in order to fill those data elements of the T-object which have no direct counterpart. For example, the Amazon parameter product carrying the value “book” is mapped to a data element “product_name” and “product_category” of the T-object. The data element “product_category” may for example serve to distinguish between consumer goods or capital goods.  
      The following basic service “TT calculation”  24  called by the TT service  20  is composed of several micro services  36 ,  38 ,  40  and  324 . First, the TT calculation  24  needs to define the appropriate jurisdiction to be applied using the corresponding micro service  36  to which the necessary parameters are passed via the T-object data model using the Web-based technology XML. The content service  22  provides the rules in the form of an additional meta data model for the determination of the specific jurisdiction to be applied. The “jurisdiction” micro service  36  in this case In which the “ship_from” parameter is “DE” (which stands for Germany) and the “product_category” is “consumer goods” determines the appropriate jurisdiction to be Germany coded as “DE” and the tax rate type to be “reduced” which are the output parameter of this specific micro service  36 .  
      The micro-service “tax rate”  38  retrieves the specific tax rate for this case from the content service  22  using an additional meta data model in which the data are also transferred using Web-based technology and XML. Finally, the micro service “calculation”  40  performs the concrete calculation of the required tax for this transaction based on the T-object data elements “net_price” and “tax_rate”. The output parameter of this micro service  40 , the tax amount, is then returned to the TT service  20  using the “return” micro-service  324  again by using XML for the data transfer.  
      As in this special example the requested TT services from Amazon are a transaction tax calculation and a logging service, the basic service “TT logging”  26  is called next from the TT service  20 . Again by using XML and handling the data over to the micro services  326  and  328  in the form of the T-object, the micro-service “log data determination”  326  determines what data have to be logged for this specific transaction. Based on the T-object element “ship_from”, the micro service  326  returns in this example the net price, the absolute tax and the invoice number to be the data elements which have to be logged. Using yet another micro service “Write DB”  328 , the determined logging data are written to the data warehouse  204 .  
      Referring to  FIGS. 5   a - e,    6  and  7 , more details are provided of the specific interface linking external applications to the basic and micro services as described in the above figures as well as linking the these services with each other. As mentioned above, an external application might use a basic or a micro service, for example the TT calculation service  24 , or one basic or micro service might use another one. Proper communication between the invoking application or service and the invoked service will be ensured by the corresponding interface which has to furnish all the data required, on the one hand, for establishing a communication between the invoking service/application and the invoked service and, on the other hand, for enabling the invoked service to perform its proper function.  
      Reference is made to the above Amazon example given in conjunction with  FIGS. 4   a  and  b . As already mentioned therewith, the interface (realized inter alia by the data mapping micro service  34 ) is used for mapping the parameters delivered in the Amazon request into the data format and model internally used by the TT calculation system  24 . If numerous different external applications all having different output parameters (data elements “net price”, “tax rate”, etc.) used the basic and micro services, a corresponding number of different data mapping micro services would have to be invoked by the TT calculation service  24  for proper communication with these applications. This, however would imply a considerable data mapping effort at the TT calculation service side.  
      Hence, according to a preferred embodiment of the invention, the data model used for communication between external applications and basic and micro services as well as between different basic and micro services (it should be noted that some basic or micro services may be externally provided and might possibly use a different data model than the internally provided basic and micro services) is standardized. It will hereinafter be referred to as tax object. The use of a standardized data model advantageously eliminates the need for complicated interface structures since now each interface only needs to implement a data mapping of the internally used data model to the standardized data model and vice versa. In other words, each service only receives data implemented in the standardized data model object irrespective of the application sending these data and, in turn, delivers only data in the standardized data model to any other application/service.  
      Returning to the specific model depicted in  FIG. 1 , any external application invoking sequentially or in parallel several of the basic or micro services, for example first of all the TT calculation service  24 , then the TT logging service  26  and finally the TT filing service  30 , needs only one mapping module at the application side for mapping its application-specific data elements to the respective data elements in the standardized data model irrespective of the specific invoked basic service. Moreover, if the respective invoked service internally uses the standardized data model no further mapping will be required at the service side. In practice, however, it might be further necessary to transmit some additional data not yet provided in the standardized data model, for example for controlling the communication between the invoking and the invoked application/service. This will often be the case for the different basic and micro services described with regard to FIGS.  1  to  4  when communicating with each other. In view of the numerous communications in the overall set of links between external applications and internal services a data model comprising data in the standardized data model as, well as individual data will be preferred wherein the individual data are necessary for the particular communication between a particular pair of applications/services. These individual data might consequently require an individual mapping at the interfaces on the application and the service side. An overall standardized data model also covering all these individual data elements seems to be less preferred since, depending on the way data is exchanged, the transfer of a large amount of data may be required.  
      In a preferred embodiment, the interface at the service side might comprise a mapping module  34 , as shown in  FIG. 4   b , realized in the form of a micro-service within the structure of the TT services  20 . This mapping module  34  will be invoked by the process and communication layer  6  of the TT services  20  upon receipt of a tax calculation request (or any other request, calling one of the basic or micro-services) wherein such an external request comprises the application-specific data elements. The mapping module then serves to convert the application-specific data elements into the standardized data model which will be used by most or all of the basic or micro services invoked by the process and communication layer  6  in connection with the particular external request, for example the external tax calculation request. As described with regard to the TT services  22  to  40  as shown in  FIG. 1  most of the basic services invoke a couple of micro services. Hence, the communication between these micro services and the invoking basic service uses the standardized data model advantageously omitting further mapping procedures.  
      In another preferred embodiment, the mapping of the application-specific data elements into the standardized data model might alternatively take place at the external application interface advantageously pre-empting the need to invoke the data mapping  34  at the TT services side. Naturally, even in the latter case such a data mapping  34  at the TT services side will be required if any one of the micro or basic services internally uses a different data model. In this case, the data mapping  34  comprises a mapping from the standardized data model into the internally used data model and vice versa when invoking this particular micro or basic service.  
      A preferred embodiment for an interface structure will now be described with respect to  FIGS. 5   a - e.  wherein one part of the: interface is implemented at the TT services side  20  and the other part is implemented in the form of an external interface at the application side.  
       FIG. 5   a  shows a simplified schematic diagram of such an interface used between an external application and the TT services  20 . In  FIG. 5   a , reference number  500  designates an external business application a part of which is described in  FIG. 5   b . In the particular example shown in  FIG. 5   b  the business application comprises a sales order module performing inter alia the steps shown in this figure. In a first step  502 , a sales order is created, which is followed by a second step  504  in which item data (material number, quantity, etc.) are added. In a subsequent step  506 , a pricing for the item is performed which requires the addition of the specific tax calculated for this item. In order to complete the tax calculation, in a subsequent step  508 , the TT calculation service  24  is invoked via an HTTP request delivering the specific data elements necessary for the tax calculation. The TT calculation service  24  calculates the tax and returns the calculated value to the business application which transfers the calculated tax back to the pricing in a step  510 .  
      As can be seen from  FIG. 5   a , the communication between the business application  500  and the TT calculation service  24  is performed via a transaction tax standardized interface  512  using a standardized data model, namely the tax object (see below). The interface  512  requires a data mapping  514  and a processing/communication  516  on the business application side and a data mapping  518  and processing/communication  520  at the TT calculation service side (for example performed inter alia by the data mapping micro service  34 ).  
      The interface processing  516  and  520  on either side provides error handling (checking for erroneously transmitted or missing data, interface errors, tax engine errors, etc.), a specific calculation request handling (a credit/return, reference to former invoice, etc.), transaction type (sale, purchase), exemption processing, audit file processing, number of records, exemption certificate determination, document summary, etc.) and a special processing (line item/end of invoice, etc.). The particular data mappings  514  and  518  will be discussed in detail with reference to  FIG. 6  below.  
       FIG. 5   c  shows a simplified diagram illustrating steps performed by the interface  512  between the business application  500  and the TT calculation service  24 . Invoking the TT calculation service  24  in step  508  in  FIG. 5   b  comprises mapping of data according to the application-specific data model to data of the standardized data model in step  522 , transferring the mapped data in step  524  and mapping the transferred data to service understandable data in step  526 , for example, to the particular program code used by the TT calculation service  24 . On the other hand, returning the calculation result of the TT calculation service  24  to the application  500  comprises mapping of the service understandable data to data according to the standardized data model in step  528 , transferring the mapped data via the Internet in step  530  and mapping the transferred data into the application data, i.e. the particular parameters used in step  510  of  FIG. 5   b,  in step  532 . Besides, the interface architecture is configured to deal with single data items as well as with a set of data items grouped to a data record.  
      Reference is now made to  FIG. 5   d  illustrating the steps shown in  FIG. 5   c  in more detail. Similar reference numbers in  FIGS. 5   c  and  5   d  designate similar method steps. As can be seen from  FIG. 5   d , the mapping step  522  performed at the business application side comprises a step  532  for reading an output mapping definition, a step  534  for deriving source information based on the read mapping definition, a step  536  of mapping the source information to the tax object and a step  538  for configuring the mapping definition and delivering the same to step  532  upon request. The data transfer step  524  comprises a step  540  for calling the TT calculation service  24  (performed for example via the HTTP protocol) and a step  542  for retrieving the tax object and the calculation request The mapping step  526  comprises reading an input mapping definition from a mapping configuration routine  546 , and a step  548  of mapping the tax object to the target information. The target information is then delivered to the TT calculation service  24  which returns the calculated tax rate. The returned tax rate is mapped to the target object in step  528 . Thereby, step  528  comprises the step  550  of reading an output mapping definition which is again delivered from the mapping configuration routine  546  and a step  552  of mapping the target information (the calculated tax rate received from the TT calculation service  24 ) to the tax object. The tax object is then transferred in step  530  to the business application  500  which comprises a step  554  of sending the tax object as a calculation result on the TT services side  20  and a step  556  of retrieving the tax object and the calculation result on the business application side. Besides, the mapping steps  526  and  528  may be omitted if the TT calculation service  24  uses the standardized data model as internal data model. In this case a simple conversion of the tax object in form of a Web-transferable document (specific object in an HTTP request, etc.) into machine-readable program code will be required. However, in this case it might be further required to merely convert technical data elements used for the technical implementation of the interface which can be done in steps  540 ,  542 ,  554  and  556 . These technical data elements preferably do not form part of the tax object. The retrieved taxi object is transmitted to the mapping, step  532  which comprises a step  558  of reading an input mapping definition delivered from the mapping configuration routine  538 , a step  560  of mapping the tax object to the source information and a step  562  of deriving a source, information based on the mapping definition. The result of step  562 , namely parameters or a set of parameters understandable by the business application  500  is then transferred to step  510  shown in  FIG. 5   b  and used for further calculations within the business application  500 .  
      In steps  538  and  546 , the set of mapping rules, might be preferably implemented in the form of two tables, the first one containing header data and the second one containing item data. A rule consists of a header table record and n item table records, wherein n is equal to 1 or an integer greater than one. The two tables might be accessible by a transaction in order to externally configure the rules within these tables (rule definitions might be created via a transaction table maintenance). In other words, the rules are configurable by external access. A rule definition will be entered into the rule header and the rule item table in form of records having the structure as shown in the following diagram:  
                                                       Rule Header Table       Rule Item Table                          Rule No   →   Rule No           Rule Type       Pos No           Dst Field       Src Table           Dst Offset       Src Field           Dest Length       Src Offset           Description                      
 
      wherein corresponding records in the rule header and the rule item table which establish a specific rule (as indicated by the arrow in the above table) are defined via identical entries in the “Rule No” field (several records in the rule item table might have the same rule number meaning that they form a complex rule). Hereby, the “Rule Type” field indicates the particular mapping type selected from the group consisting of static mapping (S), constant mapping (C) and dynamic value lookup (D) (see below). The “Dst Field” field designates the particular destination field. The “Dst Offset” field designates an offset of the destination field, the “Dst length” field a length of the destination field and the “Description” field enables the user to enter a particular comment to the underlying rule (only optionally provided). The “Pos No” field in the rule item table is a counter for the record number in the rule item table belonging to a single rule (a record in the rule header table having a specific rule number might correspond to several records in the rule header table having the same rule number). The “Src Table” and “Src Field” fields define a source table and a source field, respectively. The “Src Offset” field designates an offset of the source field.  
      A first preferred mapping type, the so called static mapping, comprises assigning the value of a certain source field to a certain destination field.  
      A further preferred mapping type, the so called constant Mapping, comprises assigning a fixed value to a certain field in the destination structure.  
      Another preferred mapping type for complex mapping situations, the so called dynamic mapping, comprises assigning the mapping result of a mapping function to the destination field wherein the mapping function is based on rules and is given in the form: 
 
destination_field=mapping_function(source_field_ 1 , source_field_ 2 , . . . )
 
      Thereby, the values of the source fields “source_field 1 ”, “source_field 2 u, etc. are the input parameters of a specific mapping function which outputs its mapping result to the field “destination_field”.  
      In a preferred embodiment of the present invention, the mapping function is defined via a lookup table (together with the two above mentioned tables) having as its contents the source information of the different source fields and the corresponding mapping result, for each rule. More particularly, the lookup table preferably contains generic keys for each rule. The generic keys are formed by concatenating the contents of all source fields of a rule. For each rule, the lookup table contains an entry for a generic key and a corresponding mapping result. Hence, the mapping result for the generated generic key is read from the lookup table and moved to the destination field of the rule (as indicated by the corresponding record in the header data table, cp. above).  
      It will be appreciated that the static and constant mapping via the specific tables as described above and the dynamic mapping via the specific lookup table as described above is only one possibility for implementing mapping rules within the mapping configuration routines  538  and  546 . Another very intuitive implementation for these routines consists of establishing rules via a user definable rule definition interpreter. Those rules may be defined in a particular rule based language (for example Jnana™, Lisp, Prolog, etc.) which provides for a very intuitive user/machine-interface. Entering such rules into the mapping configuration routines  528  and  546  demands merely knowledge about the underlying business model but not of the underlying program structure. Thus, these rules: might be entered by a user with business skills only. The rule based language generally comprises an interface allowing access to external access data (defined as source fields within the rules) and allowing deliverance of external output data (defined as destination fields). The rules are entered in terms of the rule based language wherein the user with business skills needs only to know the sets of access and output data for entering the rules connecting a set of output data with a set of access data.  
       FIG. 5   e,  shows a simplified diagram of a more complex business application  500  divided into different application routines which all may benefit of the TT services  20  as mentioned above. A first routine  570  deals with the product generation requiring the exchange of data with the data warehouse  204 . This data exchange is performed via the standardized data model, namely the tax object. Further routines of the business application  500  might comprise an order generation  572 , an order management  574 , a planning  576 , a procurement  578 , a production  580  and a logistics routine  582  which all invoke the TT calculation service via the tax object (the direction(s) of the arrows between the business application modules and the the TT calculation service  24  indicates the data flow direction (inbound and outbound data elements, cp. below). All mentioned modules  570 - 584  might further exchange data with the data warehouse  204  via module-specific or data warehouse specific data models for a transaction taxation master data maintenance, as shown with reference number  590 . The same applies for the data exchange between the TT calculation service  24  and the data warehouse  204 . The overall business organization further contains a delivering module  582  and a financial management and reporting  584 , wherein the latter one invokes the TT compliance service  28  via the tax object. The TT compliance service retrieves information from the data warehouse  204  via a specific data model. The same applies for the data mining  206 .  
      According to a preferred embodiment of the invention, the structure of the tax object transferred between the business application and the TT services  20 , between external business applications or between different basic and micro services will now be described with respect to  FIG. 6 .  FIG. 6  shows three tables “Inbound Elements”, “Outbound Elements” and “Further processing elements” dividing the different data elements of the tax object into inbound elements (data elements which will be passed to a TT service  20  from an external application or an internal TT service  20 ), outbound elements (data elements which are created, calculated or changed by the TT calculation service  24 ) and further processing elements, respectively (data elements which drive special processing either within the invoking application or within the TT service  20 ). In all three tables shown in  FIG. 6  the data elements are listed in a sequential order as indicated in the first column “Field No.” (in practice, the tax object might not necessarily be sent with the data elements in the given order but may be sent as a XML document having the corresponding data element identifier). Each line of the tables contains a different data element (identified in the second column “Data element”), wherein some data elements are divided into different sub data elements (identified in the third column “Sub Data element”), for example in line  4  of the table inbound elements, the ship-from address data element is divided into the street, territory, province, country, city, postal code, state and country sub data elements.  
      Besides, the tax object is defined so as to provide data elements for at least two different jurisdictions. It has at least one data element which is used for one jurisdiction, but not for the other jurisdiction (for example, in line  32  of the table outbound elements the data element “Tax certificate applied” is US-specific), and it has at least one other data element which is used for the other jurisdiction, but not for the first one (for example, in line  92  of the table inbound elements the data element “Destination code” is EU-specific).  
      Furthermore, the tables describe in its fourth column “Type” the specific data element type for each data element, for example in line  48  the postal code is labeled as a character with five elements. The tables further show a more detailed description for each data element in their fifth columns “Description”. The table “Inbound Data elements” further indicates in its sixth column “Required” whether the corresponding data element is must be transmitted within the tax object when invoking the TT calculation service  24  (there may be different required data elements when invoking other TT services  20 , i.e. the column “Required” deals only with the particular invocation of the TT calculation service  24 ). In particular, the data elements “company-ID”, “ship-from address” and “destination/ship-to address” are the only three data elements which must be transmitted within a tax object to the TT calculation service  24 . All other data elements might be supplemented according to the special request of a TT service  22  to  40 . For example, when the TT calculation service  24  is invoked by the business application  500  as shown in  FIG. 5   b , besides the three required data elements, the data element “line item amount” (in line  120  of the table inbound elements) is transmitted within the tax object. Naturally, the transmitted tax object only contains the values of the different data elements, possibly supplemented with the corresponding data element identifier. When implementing the tax object in the form of an XML document further data elements, not yet shown in  FIG. 6 , can be easily defined for any future enhancement requirements (further processing logic, etc.).  
      For example, the tax amount calculated by the TT calculation service  24  is returned within the tax object as the data element “Calculated tax amount” (field number  48  of the table “Outbound Data elements”) to the business application  500 . Implementing the tax object in a flexible data model, for example XML, eliminates the need to transmit all data elements (inbound, outbound and further processing elements) when transmitting a particular tax object (which would involve the transmission of roughly 230 data elements each time, most of which are deactivated). Therefore a particular transmitted data record may contain only data items complying with one jurisdiction, although the interface data model comprises data elements complying with various different jurisdictions, e.g. in different countries.  
      Hereinafter, a simplified example is given for an external business application invoking a TT calculation service  24  for tax calculation and will be described in more detail on the basis of the required mapping of the application specific data model to the standardized tax object.  
      For example, the external SAP business application invokes in step  508  of  FIG. 5   d  the TT calculation services  24  which triggers an application subroutine creating a SAP export data record COM_TAX commonly used by the SAP business application for exporting data. The export data record might in this example consist of the data fields “prices_netprice” and “customer_ship from address”. Hereby, the indicator preceding the “_” indicates the source address (for example a table name, etc.) whereas the indicator succeeding the “_” indicates the field name. It is assumed that when creating this export data record the data fields “net price” and “ship from address” are filled with the particular data values “ 500 ” and “DE”, respectively. The export data record COM_TAX is transmitted to the mapping routine  522  of the interface module at the SAP business application side.  
      The mapping routine  522  requests in its step  522  the mapping configuration routine  538  for delivery of the set of configurable mapping rules which correspond to this particular external tax calculation invocation. In the specific example, the mapping rules might consist of a static, a constant and a dynamic mapping.  
      The static mapping might concern the mapping of the field “netprice” in the table “prices” to the field “line item amount” (as indicated in  FIG. 7  in line  120 ) of the tax object. The following rule creates such a mapping:  
                                                       Rule Header Table       Rule Item Table                          Rule No: 0001   →   Rule No: 0001           Rule Type: S       Pos No: 01           Dst Field: line item amount       Src Table: prices           Dst Offset: 0       Src Field: netprice           Dest Length: 10       Src Offset: 0           Description                      
 
      The rule No. 1 contains the entry “prices” in the source table field and the entry “netprice” in the source field (both mentioned entries are entered into the rule item table) and the entry “line item amount” in the destination field (this entry is entered into the rule header table). Furthermore, the value of the field “Pos No” of the rule item table is set to 1 since there is a static mapping (cp. entry “S” in “Rule Type” field of the rule header table) of the value of exactly one field in the source structure to exactly one field of the destination structure.  
      Similarly, a rule for a static mapping of the “customer_ship from address” to the destination field “ship-from address_country” (as indicated in  FIG. 7  in line  8  of the tax object, wherein the mentioned field consists of a data element field “ship-from address” and a sub data element field “country” both together forming the destination field) has the following form:  
                                                       Rule Header Table       Rule Item Table                          Rule No: 0002   →   Rule No: 0002           Rule Type: S       Pos No: 01           Dst Field:       Src Table:           ship-from address_country       customer           Dst Offset: 0       Src Field: ship from address           Dest Length: 2       Src Offset: 0           Description                      
 
      As an example for a constant mapping, the tax object might comprise a data field “version no” (provided in the reserved space table) which identifies the particular program version of the calling SAP business application. The corresponding constant rule has the following structure:  
                                                       Rule Header Table       Rule Item Table                          Rule No: 0003   →   Rule No: 0003           Rule Type: C       Pos No: 01           Dst Field: version no       Src Table:           Dst Offset: 0       Src Field: v4.01 A           Dest Length: 5       Src Offset: 0           Description                      
 
      As a result, the fixed value “v4.01.A” will be assigned to the destination field “version no”.  
      As an example for the dynamic mapping (which allows processing of the information from several source fields and mapping of the result to a particular destination field) the destination field “currency” of the tax object (cp.  FIG. 7 , line  84 ) will be considered. For example, in the country “Germany” the currency will be changed from “DM” to “Euro” at the end of year 2001 which means that the year of the transaction date is an indicator for the currency, i.e. the years . . . , “2000”, “2001” indicate the currency “DM” whereas the years “2002”, “2003”, . . . indicate the currency “Euro” for Germany. A corresponding dynamic mapping will have the following form:  
                                                       Rule Header Table       Rule Item Table                          Rule No: 0004   →   Rule No: 0004           Rule Type: D       Pos No: 01           Dst Field: currency       Src Table: customer           Dst Offset: 0       Src Field: ship from address           Dest Length: 4       Src Offset: 0           Description                   Rule No: 0004                   Pos No: 02                   Src Table: date                   Src Field: year                   Src Offset: 0                      
 
      This rule contains one record in the rule header table and two records in the rule item table as indicated by the “Pos No” field counting the number of records of a single rule in the rule item table. The information is taken from the source tables “customers and “date” and the respective fields “ship from address” and “year” whereas the mapping result is written into the destination field “currency”. The table “date” with its source field “year” might not be part of the export data record COM_TAX and should therefore be directly accessed from SAP internal tables which are not transmitted to the mapping routine  522 .  
      In the particular example given above, the lookup table will have the following entries:  
                              Lookup Table                         Rule   Key   Result               .   .   .       .   .   .       .   .   .       0004   DE2000   DM       0004   DE2001   DM       0004   DE2002   Euro       0004   DE2003   Euro       .   .   .       .   .   .       .   .   .                  
 
      Thus, when reading the values “DE” and “2001” from the source fields “ship from address” and “year” in step  534 , concatenating these values will give the result “DE2001”. This result forms a generic key such as the ones listed in the lookup table in the middle column. The corresponding mapping result “DM” is then read from the right column in the lookup table and moved to the destination field “currency” in step  536 .  
      A configuration of the rule might be performed by external access to the lookup table and changes to its content, for example by accessing the lookup table responsive to the external tax calculation call and by changing its line “0004|DE2002|Euro” into “0004|DE2002|DM” (if the introduction of the currency “Euro” is postponed to year “2003” in Germany). This configuration may be accessible via a transaction call “Change mapping configuration SAP-Tax Object” giving access to the mapping configuration routine  538  and allowing changing of the corresponding rules. The advantage of user configurable mapping rules over hard coded mapping rules lies in the easy handling of changes to these rules (as can be seen from the above example) since the user only has to deal with these rules on a business level rather than on the machine level which requires skilled programming knowledge.  
      When defining the rules via the mentioned rule interpreter, the user enters a list of rules which define the data mapping from the SAP export data model COM_TAX into the data model of the tax object. As the tax object has the specific well-defined data elements ” ship-from address_country”, “version no” and “currency” the user has for example to deal with the following questions concerning these data elements: 
          which SAP-field contains the information of the particular data element?    is this SAP-field exported via the export data record COM —TAX?      otherwise, can it be found in a SAP database table (if yes, in which table)?    otherwise, what can be done to get this information in the system (for example, can it be derived from other SAP fields). In this case, the user has to define a number of more complex rules (for example, similar to IF . . . THEN . . . constructs and the like) to evaluate this information from other SAP fields.        

      In step  536 , the destination data are brought in the particular data model language used for the transmission, for example XML. A corresponding XML document for the above example will have the following form (and might be transmitted in the body of an HTTP request):  
                                                  &lt;tax object&gt;             &lt;inbound elements&gt;               &lt;ship from address&gt;                 &lt;country&gt;DE&lt;/country&gt;               &lt;line item amount&gt;500&lt;/line item amount&gt;               &lt;currency&gt;DM&lt;/currency&gt;             &lt;/inbound elements&gt;             &lt;reserved space&gt;               &lt;version no&gt;v4.01.A&lt;/version no&gt;             &lt;/reserved space&gt;           &lt;/tax object&gt;                      
 
      In the above presentation control commands including possible error messages and the like are omitted which, however, may be part of the tax object. These commands may be entered into the tax object and removed from the same in steps  540  and  542 , respectively, where they are used for transmission control.  
      When the TT calculation service  24  has the same data model as the tax object, the mapping routine  526  in  FIG. 5   d  is reduced to a simple conversion of the XML document into a program understandable code (e.g., C ++  code, etc.).  
      The advantages of the standardized data model used for the transmission of business and control data elements can be easily seen from the above description of the simplified example. A programmer working with a particular program module (either the external SAP business application or the TT calculation service  24 ) needs only to know the particular data model of the program module he is working with and the data model of the standardized tax object but not the data model of the other program module. Consequently, he only needs to configure mapping rules (e.g. in steps  538  or  544 ) for mapping the data model of his program module to the one of the standardized tax object, and vice versa.  
      The TT logging service  26  shown in  FIGS. 1 and 3  will now be described in more detail. “Logging” means storing of transaction-tax-related transaction data. In most jurisdictions it is required that transaction data of tax-relevant transactions are recorded on transaction-by-transaction basis. Furthermore, companies have often their own interests in recording tax-relevant transaction data for business-management analysis purposes. Recording of transaction data in a way which fulfills at least the minimum requirements of the tax laws in a certain jurisdiction enables a “transaction tax compliance reporting” (for that particular jurisdiction). The logged transactions form the basis for the tax filing, i.e. the calculation of the amount of transaction tax to be paid to the tax authorities and preparation of the corresponding tax declaration which has to be made in certain time intervals, for example monthly. The logged transaction data are also used for transaction-tax review by official and internal auditors. Logged transactions may be trade invoices, general ledger (G/L) bookings (i.e. bookings in a company&#39;s general account book which appear when a payment has been received or made), etc. In most jurisdictions, it is not required to log every transaction-tax-related transaction for compliance reporting. For example, transactions with provisional character, such as offers or orders, need not be logged. The requirements as to which transactions have to be logged differ from jurisdiction to jurisdiction. They may even be different for different types of legal entities, for example corporations and partnerships. The definition of which transactions have to be logged may also be company-dependent since individual companies may wish to carry out a more comprehensive reporting than the minimum-required compliance reporting.  
      Also the definition of what data of a transition have to be logged differs from jurisdiction to jurisdiction and may depend on the company&#39;s legal type. For example, within Europe, Spain requires a more comprehensive recording of transaction data than Germany. Again, individual companies may wish to log more detailed transaction data than the minimum requirement of compliance reporting, so that the definition of what transaction data have to be logged may be company-dependent. The TT logging service  26  of  FIGS. 1 and 3  enables such a variable kind of logging.  
      The TT logging service  26  is a software component which can be invoked independently of other basic services  8 , in particular independently of the TT calculation service  24 . This enables the use of different transaction tax calculation applications to the TT calculation service  24  (for example, the use of external tax calculation provided by external service providers) without affecting the TT logging service  26 . Furthermore, it enables stored data, such as stored history or legacy data  220  generated by non-integrated tax calculation engines, to be loaded directly to the TT logging service  26 , as is indicated by an arrow in  FIG. 3 . In contrast, in the known transition tax program products, the recording of transactions is intimately linked with the tax calculation, so that only those transactions which have previously been passed through for the program&#39;s tax calculation are recorded.  
      The TT logging service  26  is invoked by an HTTP request from the process and communication layer  6  together with an argument comprising transaction-related data, for example in the form of an XML document forming the body of the HTTP request. The transaction-related data elements of the argument are preferably identical with the transaction tax object or are a subset of the transaction tax object described in connection with  FIG. 6 .  
      The rules defining which transactions and what transaction data are to be logged (called “log rules”) are contained in the content service  22  in a form configurable by the user in a filing rules and templates configuration interface  218 . The content service  22  is shared between different basic services  8 , and therefore also contains rules and “meta data” for the other basic services  8 , as shown in  FIG. 3 . In other embodiments (not shown), the content service is modular, the TT logging service then has a special log rule management service. When the TT logging service  26  is invoked it fetches all, or a subset of, the log rules and evaluates them with the data of the transaction for which it has been invoked. In the case in which only a subset is fetched, it is composed of those log rules which may be relevant for the decision whether the transaction has to be logged and what transaction data are to be logged. For example, in a transaction in which a good is shipped from Germany by a German seller, the subset of rules fetched from the content service  22  comprises all the log rules which relate to Germany.  
      The log definition is not hard-coded in the content service or the logging service application. Rather, the log rules can be input and modified by the user in a log rule configuration interface  214  which is part of the content service  22 . The log rules can be entered by the user online in the form of a script language., After having fetched the script language log rules, the TT logging service  26  interprets them and processes the log request accordingly.  
      The TT logging service  26  has an auto-recognition functionality: it can decide itself whether a transaction is to be logged, and, if applicable, what data of the transaction are to be logged, by evaluating the log rules with data of the present transaction received together with the HTTP request which has invoked the TT logging service  26 . Therefore, no previously invoked component (for example, the calculation service  22 ) needs to decide whether the present transaction is to be logged or not (if such a decision were taken by a previous component, the logging service could only be invoked when logging is required). Rather, since the TT logging service  26  takes this decision itself, it can be invoked for every event (i.e. for every transaction) without any parameter representing a log requirement. As a consequence, any application generating transactions can be used together with the TT logging service  26  without having to take care itself whether transactions have to be logged. This auto-recognition functionality enhances the modularity of the whole transition tax application since it enables the log requirement information to be concentrated in the content service  22  and the logging service  26  and the other services can be kept free of it.  
      The following table illustrates in a simplified way the log requirement rules for two different jurisdictions (“countries”) and three different transaction types:  
                                                   country X   country Y                                                        order   no logging required   no logging required           invoice   logging required   logging required           payment   no logging required   logging required                      
 
      When the TT logging service . 26  is invoked with the data of a transaction as parameters, it evaluates the log requirement rules with the parameter data. If, in the above-mentioned example, the country of a transaction is “X”, and the transaction type is “order” or “payment”, no logging is performed. If, in contrast, the country is “X” and the transaction type is “invoice”, logging is performed, based on further rules which define what transaction data have to be logged for the present transaction. For example, for a certain country with low logging requirements, only the invoice number, net price and tax of the transaction are logged. In a country with more comprehensive logging requirements, further transaction data, such as the buyer registration number, the product description, the tax rate applied, etc. are logged. If the country of origin is “Y” logging is also performed for the transaction type “payment”, in the above example.  
       FIG. 7  is an exemplary flow chart of a method carried out by the TT logging service  26  of  FIGS. 1 and 3 . In step  602 , the TT logging service component  26  is invoked, for example by receiving an HTTP request with transaction data as argument, which may be in the form of an XML document included in the body of the HTTP request. However, any other suitable invocation mechanism may be used. In step  604 , the log rules which may be relevant for the present transaction are fetched from the content service  22 . In step  606 , the log rules are evaluated for the present transaction data and it is ascertained whether logging is required. If the answer is negative, in step  608 , a flag is set in the transaction data to be output as an XML parameter list indicating “Transaction has not been logged”. In step  610 , the call to the TT logging service  26  is returned by sending an HTTP response with the XML parameter list to the origin of the original HTTP request. However, if the answer in step  606  is positive, the log rules are evaluated in step  612  as to what data have to be logged, using the input transaction data. In step  614 , the data set to be logged is prepared (e.g. a data set consisting of invoice number, net price and tax). In step  616 , the prepared data set is stored in the data warehouse by sending a corresponding request together with the data set to the data warehouse component  204 . In step  618 , a flag is added to the transaction data to be output as an XML parameter list indicating “Transaction has been logged”. In step  620 , the call to the TT logging service  26  is returned by sending an HTTP response with the XML parameter list to the origin of the HTTP request received in step  602 .  
      In other preferred embodiments (not shown), the function of the TT logging service is extended so that it also may preselect transactions which require a transaction tax calculation. In order to carry out such a pre-selection, the logging service is then invoked before the invocation of the TT calculation service for the first time. In these embodiments, it fetches and evaluates rules which indicate whether a transaction tax calculation is required for a given transaction, sets a corresponding flag and returns the transaction data together with this flag. Depending on the existence or absence of this flag, the process and communication layer  6  will then invoke the TT calculation service or will skip it. The logging service can be invoked a second time in order to perform the actual logging process, as was described above.  
      By using the described logging service it is ensured that the logged data are in compliance with the requirements of the pertinent jurisdiction. One and the same logging service can be used for the different jurisdictions of interest. The “content”, i.e. the rules reflecting the logging requirements of the different jurisdictions can easily be configured by the user via a user interface, without the need to change hard-coded programs. The logging service can be invoked independently of other program components, such as transaction tax calculation components, and does not need logging-specific invocation parameters in order to perform the logging task. This enables the process layer to use independent services for TT calculation and TT logging. For example, an external service provider can be used for TT calculation, but the TT logging can be performed in-house by using the described TT logging service. Alternatively, a TT logging service of the described kind can be offered as an e-service over the Internet. Such a service will not require the customer to specify whether and how a logging has to be performed for a given transaction. Rather, this determination can be offered as a part of the e-service.  
      The TT filing service  30  of  FIGS. 1 and 3  enables automatic preparation and filing of transition tax declarations for different jurisdictions.  
      Conventionally, transactional data, mostly in aggregated form, is retrieved by various reports, which are consolidated manually. Tax declaration forms have to be obtained from the tax authorities and filled out manually, based on the results of the manual report consolidation. The preparation of tax declarations for different jurisdictions requires different ways of processing, and even changes of the official requirements in one jurisdiction may require changes in the processing. In contrast, the filing service  30  enables the tax declaration and filing to be carried out automatically. The processing is the same for different jurisdictions and remains unchanged when official requirements are changed. The filing service  30  is based on logged transaction data which have previously been generated by the logging service  26  or any other suitable logging application. Since the data of certain transactions (in particular booking transactions) may be incomplete, the auto-completion service  42  ( FIGS. 1 and 9 ) is invoked preferably by the TT logging service  26  before logging the incomplete transaction data or after the logging step, but before the filing service  30  is invoked. The auto-completion service  42  completes such incomplete transaction data which enables the preparation of the tax declaration according to the tax compliance requirements without manual intervention.  
      A tax declaration normally represents an aggregation of transaction data, in particular the calculation of total numbers, such as the total amount of transition tax received in the declaration time period. In jurisdictions with value added tax, also the total amount of transition tax paid in the declaration time period as well as the difference between the received and paid amounts are calculated. Typically, the declaration has to be filed within short time intervals, for example monthly.  
      In order to initiate the filing process, the user has to input a corresponding request to the process and communication layer  6  ( FIG. 1 ) via a user interface. Together with the request, the user has to indicate for which country or jurisdiction the declaration shall be filed. In other, alternative embodiments, the tax filing process is initiated automatically when certain legal conditions are fulfilled, for example when the term of a tax declaration interval is reached, e.g. on the last day of each month. The process and communication layer  6  translates the user request or the automatically generated request into an HTTP request sent to the filing service  30 . The request has an argument representing tax-filing-related information, such as the country or jurisdiction of the declaration to be prepared, the name of the company for which the declaration is to be prepared (if the automatic tax declaration filing is offered as a service for several companies); the time period which shall be covered by the tax declaration, etc. Moreover, process-related data, Such, as an identification of the user who has initiated the filing process, is transmitted as argument. The argument data can, for example, be in the form of an XML document forming the body of the HTTP request. However, any other suitable invocation and parameter transmittal mechanism may be used.  
      In  FIG. 8  the filing service  30  is shown in more detail. It is composed of a request verification component  702 , a tax filing determination component  704 , a transaction data selection component  706 , a report execution component  708 , and a tax filing component  710 . The incoming tax filing request from the process and communication layer  6  is first processed by the request verification component  702 . It verifies that certain conditions are fulfilled, for example, that the user who has initiated the filing process is authorized to do so, that the specified country or jurisdiction is existent and is one of the countries/jurisdictions which can be processed by the filing service  30 , that the time interval for which the preparation of a tax report is requested is correct, etc. If the outcome of the request verification is negative, the tax filing process is either terminated (e.g. if the user is not authorized) or a message is sent to a message handler  712  asking for a confirmation by the user or another kind of user intervention (for example, if the tax declaration processing for the specified country and time interval has already been carried out, the user is asked to confirm that it should be repeated).  
      However, if the result of the request verification is positive, the tax filing determination component  704  is activated. Its task is to fetch report content rules and tax declaration templates for the country or jurisdiction for which the tax declaration shall be prepared from the content service  22 . To this end, the tax filing determination component  704  sends a corresponding request to the content service  22  which, in turn, returns the requested rules and templates.  
      Then, the transaction data selection component  706  is activated. Its task is the selection of the transaction data records which are required for the preparation of the tax declaration on the basis of the original filing request and the rules received from the content service  22 . More precisely, the transaction data selection component  706  has the actual selection carried out by the data warehouse  204 . To this end, the selection component  706  translates the definition provided by the report content rules as to what transaction data are needed for the preparation of the present tax declaration into a corresponding Standard Query language (SQL) data retrieval command. This SQL command is sent to the data warehouse  204 , which in turn processes it, i.e. selects transaction data records from the stored transaction data according to the SQL command and returns the selected transaction data to the transaction data selection component  706 .  
      After or during the data selection process, the report execution component  708  is activated. It has mainly two tasks: Its first task is to consolidate the selected transaction data. Consolidation means determination of numbers characterizing the selected transaction data globally, for example the total number of transactions, the accumulated amount of transaction tax received, the accumulated amount of transaction tax paid, the difference of these two accumulated amounts, etc. The way in which the transaction data are to be consolidated is also defined in the report content rules fetched from the content service  22 . The second task of the report execution component  708  is to enter the results of the transaction data consolidation into the corresponding fields of the text declaration template, which has also been received from the content service  22 . The result is a finished tax declaration in compliance with the legal requirements of the jurisdiction in which the declaration is to be filed. In some jurisdictions, it may be required to present not only consolidated data, but also individual transaction data. For these jurisdictions, the report execution component  708  appends a data record for each transaction in the legally required format, which can also be defined by the report content rules fetched from the content service  22 .  
      The result of the process carried out by the report execution component  708  is a finished tax declaration in electronic form. For jurisdictions which allow an electronic filing of transaction tax declarations, the tax filing component  710  is then activated. It prepares the electronic tax declaration for transmission over a network (e.g. by encrypting it), opens a network connection to the tax authority&#39;s receiving server and dispatches the tax declaration prepared in such way to the tax authority&#39;s receiving server. The network used for this dispatch may be the Internet or, for example, a telecommunication network which allows point-to-point access (such as a public telephone network). Also the actual payment of the accumulated transition tax may be effected automatically via an electronic bank transfer. To this end, an electronic transfer component (not shown) is provided in certain preferred embodiments. If, however, the jurisdiction for which the tax declaration is to be prepared does not allow electronic filing of transition tax declarations, a hard copy of the electronic tax declaration prepared by the report execution component  708  is printed out and sent as a paper document to the tax authority.  
      The filing service  30  also has a tracing functionality. All steps carried out by the several components of the filing service  30  can be reported in the form of trace records which are stored in the data warehouse  204 . This enables the user to trace how the numbers appearing in the finished tax declaration have been generated. The tracing functionality not only serves as a debugging instrument. It can also serve as a proof for the correctness and compliance of the way in which the tax declaration has been prepared. Based on the stored trace records, an official or internal auditor can verify the correctness and compliance of the tax declaration.  
      A user confirmation may also be requested at other stages of the tax filing preparation process than the above-described request verification stage. For example, before carrying out the actual electronic filing of the tax declaration by means of the tax filing component  710 , the filing service  30  asks for a user confirmation. In addition, in preferred embodiments, the filing service  30  enables the user to intervene manually at different stages of the text declaration preparation process. For example, the user may be enabled to scan the transaction data selected by the transaction data selection component  706  and to change or discard transaction data records manually (however, it is generally preferred that such manual interaction is avoided, in particular in view of the auto-completion functionality of the auto-completion service  42  which automatically completes incomplete transaction data records. The message handler  712  provides the user interface for these confirmation and intervention tasks. The communication is carried out by messages interchanged between the message handler  712  and the filing service  30 .  
      The tax declaration templates as well as the rules which define which transaction data records have to be selected, how the selected transaction data are consolidated and where the results of the consolidation are to be put in the templates (called “report content rules”) are contained in the content service  22  in a form configurable by the user. The report content rules and the tax declaration templates are not hard-coded in a content service  22  or the filing service application  30 . Rather, they can be input and modified by the user in a report content rules configuration interface  714  and a tax declaration templates configuration interface  716  which are both part of the content service  22 . The report content rules can be entered by the user online in the form of a script language. After having fetched the script language content rules, the filing service  30  interprets them and processes them accordingly. As already mentioned above, the content service  22  is shared between different basic services  8 , and therefore also contains rules and “meta data” for the other basic services  8 , as shown in  FIG. 3 . In other preferred embodiments (not shown) the content service is modular, the TT filing service.  30  then has a specialized report content service component Although it is generally possible that the filing service  30  fetches all report-related rules and templates, it is, preferred that it fetches only that subset of rules and templates which is relevant for the jurisdiction or country for which the tax declaration is being prepared.  
      By using the described tax filing service, it is ensured that the evaluation of transaction tax data and the resulting tax declaration are in compliance with the requirements of the pertinent jurisdiction. One and the same filing service can be used for different jurisdictions, and the processing steps to be performed by the user are the same for all jurisdictions. The “content”, i.e. the rules reflecting the tax declaration requirements as well as the templates can easily be configured by the user via a user interface, without the need to change hard-coded programs. The tax declaration is prepared automatically and can be filed electronically. The filing service is independents of other program components, such as transaction tax calculation components and logging components. This enables the process layer to use independent services for TT calculation, TT logging and TT filing. For example, an external service provider can be used for TT calculation, but the TT logging can be performed in-house by using the described TT filing service. Alternatively, a TT filing service of the described kind can be offered at an e-service over the internet. The transaction data records could, for example, be resident at the e-service&#39;s customer and send to the tax declaration service provider together with the request over the Internet.  
       FIG. 9  shows a exemplary flow chart of a method carried out by an auto-completion service module  42  according to a preferred embodiment of the invention. In the interest of a better understanding of this particular embodiment the normal situation when calling a particular TT service  22  to  40  will be briefly explained. Each time a particular TT service  22  to  40  is called a set of data elements, for example in the form of the tax object, might be transmitted which will be used by the called TT service  22  to  40  for performing its proper function. Furthermore, the called TT service  22  to  40  might have access to further data elements, such as are stored in the data warehouse. However, the situation might occur that a particular TT service  22  to  40  needs further information in order to accomplish its internal operations. This might be best seen with respect to the particular example of the logging service  26 . When invoking the logging service  26  for logging tax-relevant information the situation might occur that the invoking TT service  22  to  40  transmits data elements which it generally considers to be sufficient for the logging service  26  to accomplish the logging operation. In particular, an invoking TT service  22  to  40  or external application might transmit all booking data listed in the general account book for a specific payment which has been received or made. However, the logging service  26  might, recognize on the basis of the fetched logging rule for a particular country that it requires logging of the corresponding invoice number and date as well (for example in Germany, some legal entities like partnerships have to log balancing reports including invoice dates). This invoice number and invoice date might not be transmitted among the data elements. According to the prior art a dialog with the user had to be opened enabling the user to manually enter the missing information.  
      According to the preferred embodiment of the invention shown in  FIG. 9  this detrimental situation will be avoided as follows: If the logging service  26  recognizes that it is not able, to log a particular data element as required by the applied logging rule it might call the auto-completion service  42  depicted in  FIG. 9 . Thereby, it transmits transaction-related data elements comprising the missing data element identifier. The transaction-related data elements may further comprise all data elements currently used by the logging service  26  for complying with the actual logging event. These data elements are preferably identical with or a subset of the standardized data model, the tax object, described with respect to  FIG. 6 . In the example shown in  FIG. 9  the auto-completion service  42  is a software module forming a basic service which can be invoked independently of other basic services, for example by an HTTP request from the process and communication layer  6 . Alternatively, the auto-completion service  42  might bee implemented as a micro service in the overall TT structure or might be directly integrated in form of a software component into the particular calling service (in this example into the logging service  26 ). Naturally, all other TT services  22  to  40  as discussed with the respect to FIGS.  1  to  8  may benefit from an auto-completion function. In particular, the TT compliance report service  28  profits from such an auto-completion function as a lot of transactions like direct G/L entries do not carry all information required by the particular compliance report. Moreover, as discussed with respect to  FIGS. 1 and 3  the compliance report service  28  may consider different reporting areas (management, audits, etc.) all having different reporting needs. Finally, it will reduce different interpretations of these kinds of transactions by different users and enable one compliance view. In addition, the various different data extractions for compliance reporting will be reduced to exceptions only. The preferred embodiment particularly solves the problem of the prior systems that hard copied information needed to be stored somewhere in the system in order to enable tracking and verifying correctness of transactions (which often was forgotten and needed to be manually added for each transaction).  
      Returning to  FIG. 9  the steps performed by the auto completion service module  42  will be discussed in more detail. In step  802  the module  42  receives the transmitted data elements (for example by means of an interface component), in particular the missing data element identifier. In an optional step  804  it might fetch a set of completing rules from the content management service  22  in a user-configurable form. As already discussed with respect to the logging service  26  shown in  FIG. 7  the content management service  22  also contains other rules and “meta data” for other basic services (see above). The auto completion service  42  might fetch only a subset of completing rules concerning the particular missing data element. If the step  804  is not provided the auto completion service  42  might contain an internally stored set of completing rules for all or a subset of missing data elements (in the latter case, different auto completion services  42  associated to different TT services  22  to  40  may be provided which only need the subset of missing data elements occurring in the specific TT service  22  to  40 ). In a step  806  it applies the set of completing rules (for example by means of an evaluation component) with regard to the missing data element while having access to the transmitted data elements as well as to data elements stored in the data warehouse, etc. In general, the completing rules are similar to the mapping rules described with regard to the above preferred embodiments of the invention. The difference, however, between these rules lies in the specific certainty a missing data element might be identified by both sets of rules. In the above mapping rules, each data element is exactly determined from one or a set of source fields (in the above example, the “line item amount” used by the TT calculation service  24  is exactly determined from the source field “prices_netprice”, similarly, the “currency” is exactly determined from the “customer_country” and “date_year” source fields). If for example a booking in the general account book lacks the corresponding invoice number(s) or date(s) (cp. above) this number might be derived from the customer name identified among the information for this booking. A corresponding completing rule might enable the auto-completion service  42  in step  806  to search the data warehouse for the customer name and for corresponding invoice numbers. The simplest case occurs if only one invoice number will be found. Then, the booking will most probably correspond to the found invoice number which may be further verified by comparing the found invoice amount and the booking amount in the ledger. A more complicated case occurs if several invoice numbers are found and none of the corresponding invoice amounts corresponds to the booking amount in the ledger. Then, a kind of artificial intelligence implemented in more complex completing rules might try to add all open invoice amounts or all combinations of open invoice amounts and compare the results with the booking amount. A correspondence between such a combination and the booking amount implies a likely relationship of the missing invoice numbers and the booking amount.  
      Preferably, the completing rules are not hard coded in the content management service  22  or the auto-completion service module  42 . Rather, the completing rules can be input and modified by the user via a completing rule configuration interface which may be part of the content management service  22  or the auto-completion-module  42 . The completion rules can be entered by the user online in the form of a script language.  
      Moreover, the “intelligent” completing rules might be configured to consider jurisdictional requirements when completing missing information. For example, if an outside invoice merely shows the gross amount (i.e. the before-tax amount and the value added tax rate are added and not separately listed in the invoice) the auto-completion service module  42  might calculate the value added tax rate on the basis of the addressee&#39;s location, the corresponding jurisdiction to be applied and the listed gross amount. However, some jurisdictions (for example the German jurisdiction) might generally forbid the derivation of value added tax rates from gross amounts. Consequently, in such a case, the auto-completion service  42  might notify the user about this particular event in a step  808  (for example by means of an optional notification component), i.e. that it will consider the gross amount not to contain a value added tax rate. Generally, if the applied completing rules lead to the result that the missing data element should not be derived from other information due to legal or other requirements the user will be notified and the auto-completion service  42  returns to the invoking service in step  810 .  
      Otherwise the likelihood of the determined value for the missing data element to be valid will be evaluated in a plausibility test  812  (for example by means of a plausibility checking component). Therein, the likelihood may either be determined on the basis of a fixed certainty value associated with the corresponding completing rule leading to the determined value for the missing data element. This fixed certainty value might for example indicate that this completing rule leads most likely or only vaguely to the information for the missing data element. Apparently, there are numerous other possibilities for deriving such a certainty value. Preferably, the plausibility test returns the certainty value according to the following procedure. As can be seen from the above particular examples, there are numerous possibilities for implementing completing rules deriving information about missing data elements. Therefore, several different completing rules may be configured to get several suggestions about the missing data element from several different sources. The set of suggestions obtained will then be evaluated by means of the plausibility tests. A very simple plausibility test would consist of comparing all suggestions delivered by this set of completing rules and setting a certainty value either to “most likely” if all suggestions are equal to each other or to “vague” if at least one suggestions differs from the other ones.  
      The service module  42  then proceeds to step  814  where the certainty value is compared with a predetermined threshold parameters, for example “most likely” and “vague”. If the certainty value is equal to “vague” the auto-completion service  42  proceeds to step  816  where it opens a dialog routine with the user suggesting its particular result or results for completing the missing data element and asking for confirmation of the suggested result or for selection of one of the several results. Furthermore, the user might be enabled during this dialog to enter a completely different value for the missing data element if the suggestions are not acceptable. Naturally, the service  42  also proceeds to step  816  when it is unable to obtain any value for the missing data element and asks for manual entry of the data element.  
      If in step  814  the certainty value is determined to be equal to the threshold parameter “most likely” the auto-completion service  42  will directly proceed to step  818 . Similarly, step  808  subsequently proceeds to step  818  either with the confirmed suggestion, the selected suggestion of the missing data element or the user-entered value of the missing data element. In step  818  the auto-completion service  42  returns the missing data element to the invoking TT service  22  to  40 .  
      Summarizing, subject to certain reporting requirements defined by tax authorities (cp. the description with respect to the filing service  30 ), by the company management, the audit requirements and others as appropriate, the auto completion service  42  intelligently and as far as possible automatically calculates or supplies missing information.  
      With the preferred embodiments, a more flexible linking of a business application to a component of a computer-based transaction tax processing system is provided than it was previously the case. Thus, a general purpose of the preferred embodiments is to provide an improved software interface for a flexible data mapping, a improved method and a improved computer program product.  
      All publications and existing systems mentioned in this specification are herein incorporated by reference.  
      Although certain methods and products constructed in accordance with the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this, patent covers all embodiments of the teachings of the invention fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.