Abstract:
A method, apparatus and program storage device is provided for mapping data objects residing in multiple data sources, or generated dynamically, into a single or multiple, reusable software components, for integrated information access to multiple disparate data sources, residing on or generating the data dynamically on different hardware systems and possibly in different data formats. The method has steps for identifying data objects in multiple data sources, employing an information integration software facility for connecting to the data sources containing the data objects and registering the data objects, creating at least one virtual data object having at least one attribute from the selected registered data objects, and a step for wrapping access to the at least one virtual data object into a reusable software component, as though it was a single real data object, accessible directly from software applications.

Description:
[0001]     The present invention is a continuation-in-part which specifically claims the benefit of and discloses and claims subject matter disclosed in a related earlier co-pending parent patent application entitled: “Mapping Data From Multiple Data Sources Into a Single Software Component” by the same two inventors Saracco and Wolfson, Ser. No. 10/644,483, filed on Aug. 20, 2003, attorney docket no. STL9200000107US2, assigned to the assignee of the present invention and fully incorporated herein by reference, allowed on Aug. 1, 2004.  
         [0002]     The parent invention entitled: “Mapping Persistent Data in Multiple Data Sources Into a Single Object-Oriented Component” was a continuation-in-part which specifically claims the benefit of and discloses and claims subject matter disclosed in a related earlier co-pending parent patent application entitled: “Mapping Persistent Data in Multiple Data Sources Into a Single Object-Oriented Component” by the same inventors, Ser. No. 09/764,611, filed on Jan. 17, 2001, attorney docket no. STL9200000107US1, assigned to the assignee of the present invention and fully incorporated herein by reference, issued on Oct. 14, 2003 under U.S. Pat. No. 6,633,889 B2. 
     
    
     BACKGROUND OF THE INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     The present invention generally relates to database management systems, and, more particularly, to mechanisms within computer-based database management systems for mapping disparate-data residing in multiple data sources or generated dynamically into a single or multiple, reusable software components accessible to application developers.  
         [0005]     2. Description of Related Art  
         [0006]     The increasing popularity of electronic commerce has prompted many firms to turn to application servers to deploy and manage their Web applications effectively. Quite commonly, these application servers are configured to interface with a database management system (DBMS) for storage and retrieval of data. This often means that new Web applications must work with “legacy” environments. As a result, Web application developers frequently find they have little or no control over which DBMS product is to be used to support their applications or how the database is to be designed. In some cases, developers may even find that data critical to their application is spread across multiple DBMSs developed by different software vendors.  
         [0007]     The e-commerce community commonly uses entity Enterprise JavaBeans (EJBs) when persistence is required, that is, when data associated with Java objects must continue to exist (or persist) beyond the boundaries of an application session. Most frequently, entity EJBs use a relational DBMS for such storage purposes. EJB developers can create one of two kinds of entity EJBs: those with container-managed persistence or those with bean-managed persistence. Container-managed persistence is often favored, as it relieves the bean developer from writing the data access code; instead, the system running the container in which the EJB resides will automatically generate and execute the appropriate SQL as needed. By contrast, entity beans with bean-managed persistence require the developer to code and maintain his/her own data access routines directly. This allows for more flexibility, but requires additional programming skills (such as greater knowledge of DBMS technology), increases labor requirements for bean development and testing, and potentially inhibits portability of the bean itself. Unfortunately, firms intent on using container-managed entity EJBs (CMP entity beans) for their e-commerce applications may encounter some stumbling blocks. The firm&#39;s Web application server of choice may not support the firm&#39;s DBMS of choice. Furthermore, if design requirements call for a CMP entity bean whose attributes must span multiple “legacy” DBMSs, this almost certainly will not be supported.  
         [0008]     Presently, there is no possibility to map data that are dynamically generated or residing in multiple data sources into a single or multiple, reusable software components accessible to application developers. As an example, we may consider the situation in which a Java application developer needs to build a Web-based application that accesses critical data present in multiple data sources, each of which may reside on different systems and may store data in different formats. Moreover, the developer might wish to perceive data in these sources as a single Java object, as doing so would greatly simplify design, development, and maintenance issues. As a result, s/he might want to model this single Java object as an entity bean, Enterprise JavaBean (EJB), that uses container-managed persistence (CMP). Since EJBs are standard Java components supported by a variety of leading information technology vendors, they offer many potential business benefits, such as increased portability and high degrees of code reuse. Those EJBs that are container-managed place a minimal programming burden on developers.  
         [0009]     Unfortunately, current vendor support for CMP entity beans involves access to only a single data source per bean. Thus, the developer is forced to turn to more complex (and potentially cumbersome) alternatives to gain access to needed data sources. Often, the alternatives are more costly and time-consuming to implement, require a more sophisticated set of skills to implement, and may consume additional machine resources to execute.  
         [0010]     One presently available solution to this problem, when a Java application developer needs to build a Web-based application that accesses critical data present in multiple data sources, involves manually simulating transparent access. In that case a programmer takes on the burden of writing the software to individually connect to each of the necessary data sources, read in any necessary data, correlate (or join) the results read in from multiple data sources, perform any necessary data translations, etc. This is a substantial amount of work and is well beyond of the skill level of many programmers. Furthermore, it incurs a great deal of cost.  
         [0011]     Moreover, a developer would have to forego the use of CMP entity beans and instead employ entity beans with bean-managed persistence (BMP). These are more time-consuming to write, as well as more difficult to debug than CMP entity beans. In addition, they require considerable knowledge of the application programming interfaces (APIs) of each data source involved and afford less opportunity for query optimization, which may inhibit performance.  
         [0012]     Another presently available solution to the problem calls for a physical consolidation of the data, where the data from different data sources have to be copied into a single data source, which a programmer will then access. However, this raises issues involving data latency and added cost. Due to the data latency, copies of data will be slightly to significantly “older” than data contained in the original data sources. Working with out-of-date (and potentially inaccurate) data can be unacceptable to many applications. Increased costs include software costs, since additional software must be purchased, installed, configured, and maintained to copy data from one source to another on a scheduled or periodic basis, as well as the labor costs involved with it. The software must support data migration effort or implementing a data replication process that supports very low data latency.  
         [0013]     Therefore, there is a need to provide a method and a system which can map disparate data residing in multiple data sources into a single or multiple, reusable software components, accessible to application developers. This would simplify the design, development, and maintenance of applications and, in some cases, provide applications with a function that would otherwise be inaccessible.  
       SUMMARY OF THE INVENTION  
       [0014]     The foregoing and other objects, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments which makes reference to several drawing figures.  
         [0015]     One preferred embodiment of the present invention is a method for mapping disparate data objects from multiple data sources into a single or multiple, reusable software components accessible to software application performed by a computer, for integrated access to the disparate data objects generated dynamically by or contained in multiple data sources stored in at least one electronic storage device coupled to the computer. The method has the following steps: 
        (a) for a software application, identifying data objects for mapping;     (b) employing an information integration software facility for registering the data objects;     (c) using the information integration software facility for creating at least one virtual data object having at least one attribute from the selected registered data objects; and     (d) wrapping access to the at least one virtual data object into a reusable software component accessible directly from the software application.        
 
         [0020]     Another preferred embodiment of the present invention is an apparatus implementing the above-mentioned method embodiment of the present invention.  
         [0021]     Yet another preferred embodiment of the present invention is a program storage device usable by a computer tangibly embodying a program of instructions executable by the computer to perform method steps of the above-mentioned method embodiment of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     Referring now to the drawings in which like reference numbers represent corresponding parts throughout:  
         [0023]      FIG. 1  illustrates a flowchart of the preferred method embodiment of the present invention; and  
         [0024]      FIG. 2  illustrates a block diagram of a system implementing the preferred method embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     In the following description of the preferred embodiments reference is made to the accompanying drawings which form the part thereof, and in which are shown by way of illustration of specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the present invention.  
         [0026]     The present invention is directed to a method, program storage device with computer usable instructions, and a system for mapping disparate data from multiple data sources into a single or multiple, reusable software components accessible to application developers. Then, application developers, such as Java developers, and third-party software packages can reference the single reusable software component in lieu of directly referencing multiple different data sources, possibly stored in different formats. Moreover, existing conventional technology in an information integration server can automatically handle access to these back-end data sources in a transparent fashion.  
         [0027]     Thus, developers can create CMP entity beans whose attributes span multiple data sources. Furthermore, they can access any or all of these attributes within a single transaction. Since EJBs are standard Java components supported by a variety of leading information technology vendors, they offer many potential business benefits, such as increased portability and high degrees of code reuse. Those EJBs that are container-managed place a minimal programming burden on developers.  
         [0028]      FIG. 1  illustrates a flowchart of the preferred method embodiment of the present invention and  
         [0029]      FIG. 2  illustrates a block diagram of a system implementing the preferred method embodiment of the present invention.  
         [0030]     The method embodiment of the present invention includes the following steps, shown in  FIG. 1 . Firstly, in step  102 , a user identifies data objects in different data sources of interest, which may be stored or dynamically generated in different formats. For example, s/he may identify that certain tables residing in a DB2 database, an Oracle database, and an Informix database are relevant to his/her application. The exact nature of steps involved in data sources identification can vary. The preferred embodiment of the present invention was implemented involved issuing commands interactively, but numerous other possibilities can be employed.  
         [0031]     In the next step  104 , a user employs a software facility to connect to the data sources containing these data objects, and registers these data objects with the software facility. The software facility has to have capabilities of an information integration software server  202 , shown in  FIG. 2 , sometimes called a multi-database server or a federated data server, which has access to multiple data sources ( 204 ,  206  of  FIG. 2 ), each of which may reside on different systems and may store data in different formats. The preferred embodiment of the present invention was implemented using IBM&#39;s DB2 Information Integrator server.  
         [0032]     Afterwards, in step  106  of  FIG. 1 , using this software facility, i.e., the information integration software server  202 , a user creates one or more virtual objects (shown as element  208  in  FIG. 2 ) that consolidate single or multiple attributes from previously registered data objects from data sources  204 ,  206 . One implementation of this step may involve creating such virtual object  208  as a relational DBMS view, where such view joins data from different, sometimes remote, data sources (such as tables) based on the specific needs of the application. Each such created virtual object  208  filters data as appropriate, electing sometimes to limit the virtual object (view) to a subset of the rows and columns associated with one or more data sources (tables).  
         [0033]     In the final step  108  of  FIG. 1 , a user employs standard database connectivity mechanisms to connect to the software facility, i.e., the information integration software server  202 , and references one or more virtual data objects  208  as though their contents were derived from a single real data object. Furthermore, the user wraps access to these virtual data objects into a single or multiple, reusable software components accessible directly from a programming language application, such as a Java application  210  of  FIG. 2 .  
         [0034]     One implementation of this step of the preferred embodiment of the present invention is shown in  FIG. 2 . It may use standard SQL to establish a connection to the information integration server  202  and to read data represented by the view previously defined. For this step, a Java object, which may be a CMP entity bean, shown as Enterprise JavaBeans EJB  212  of  FIG. 2 , can be used to wrap the virtual data object(s)  208  into a reusable software component, of use to a variety of Java application  210  developers and Java-based software tools. The user may manually create this CMP entity bean EJB  212  in an EJB server  214  and adjust its deployment descriptors as desired, or s/he may employ a variety of tools (e.g., WebSphere Studio) to automate this process.  
         [0035]     Once the steps outlined above are completed, programmers can have access to a reusable object that hides the distributed nature of the data they need to access, and enables the developers to build CMP entity beans that span multiple data sources. Present technology and the current state of the art allows data access for read-only purposes. Sometimes, depending on the data contents and the information integration server technology in use, it may be possible to create CMP entity beans that support read/write access, as well. However, even a read-only restriction for such support is still a considerable improvement and facilitates efficient development of many useful business applications, thus minimizing development and maintenance costs.  
         [0036]     The preferred embodiments of the present invention were implemented in a prototype employing the following products or technologies: Java 1.3, WebSphere Studio Application Developer 5.0, WebSphere Application Server 5.0, DB2 Information Integrator 1.0, Oracle DBMS, DB2 Universal Database, Microsoft Excel spreadsheets and Informix DBMS.  
         [0037]     With the preferred embodiments of the present invention capable of mapping disparate data that reside in multiple data sources into a single or multiple, reusable software components accessible to application developers, the reach of Enterprise JavaBeans (EJB)  212  developers was extended to Web clients  218  through the integration of a Web application server  220  and information integration server  202  technologies. However, the benefits associated with integrating information integration server  202  and Web application server  220  technologies are not confined to EJBs  212 . In particular, those who prefer to include data access routines in their Web Services, Java servlets, Java Server Pages (JSPs), Service Data Objects (SDO) or persistence frameworks  222  may also benefit from transparent access to disparate data. Programmers who employ these technologies often write Java Database Connectivity (JDBC) or SQLJ calls to handle database interactions. The information integration server  202  can simplify the development task when programmers need to access data stored in multiple data sources or generated dynamically. This is accomplished by providing a common SQL API, location transparency, and (in some cases) functional compensation. In addition, joins_and unions of disparate data can be performed without manually connecting to each data source, retrieving necessary data individually from each source, temporarily storing this data in some application-managed data structure, and coding the necessary logic to handle the data integration associated with a join or union operation. Such work is handled automatically by the information integration server  202 , which presents a single-site image of data that may be physically distributed and stored in disparate DBMSs, etc.  
         [0038]     The preferred embodiments of the present invention eliminate the need for a physical consolidation of data from different sources, thus avoiding the software and labor costs involved, as well as the logical exposures introduced due to data latency problems. It also relieves programmers of the burden of writing the software needed to individually connect to each of the necessary data sources, read in any necessary data, correlate (or join) the results read in from multiple data sources, perform any necessary data translations, etc. This is a substantial amount of work and is well beyond the skill level of many programmers and incurs a great deal of cost. Moreover, the programmers do not have to possess detailed knowledge about the differences between the different data sources.  
         [0039]     Furthermore, presently, a developer would have to forego the use of CMP entity beans and instead employ entity beans with bean-managed persistence (BMP). These are more time-consuming to write, as well as more difficult to debug, than CMP entity beans. In addition, they require considerable knowledge of the application programming interfaces (APIs) of each data source involved and afford less opportunity for query optimization, which may inhibit performance.  
         [0040]     The present invention provides a means to map disparate data that reside in multiple data sources into a single or multiple, reusable software components accessible to application developers. Therefore, it simplifies the design, development, and maintenance of applications and, in some cases, provides applications with function that would otherwise be inaccessible.  
         [0041]     The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.