Abstract:
A method for indexing a database of one or more objects having one or more attributes, includes determining which of said one or more attributes should receive concatenation, concatenating those of said one or more attributes that have been determined to receive concatenation, and indexing said database with those of said one or more attributes that have been concatenated.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]     The present application is based on provisional application Ser. No. 60/486,650, filed Jul. 11, 2003, the entire contents of which are herein incorporated by reference. 
     
    
     BACKGROUND  
       [0002]     1. Technical Field  
         [0003]     The present disclosure relates to directories and, more specifically, to fast searching of directories.  
         [0004]     2. Description of the Related Art  
         [0005]     Web based applications, for example, web services, are quickly transforming the way modern businesses interact and share information. Web services are software systems for providing particular functionality over a computer network, for example, the Internet. Web services can generally be identified by Universal Resource Identifiers (URI) in a fashion that may be analogous to the way websites may be identified by Uniform Resource Locators (URLs). Web services generally contain public interfaces and bindings that enable users and other software systems such as other web services to seamlessly utilize the functionality of the web services. In this way, web services enhance the way computers communicate with users and each other.  
         [0006]     One particularly common web service is the web based directory service. Web based directory services allow for access to a directory across a computer network, for example, the Internet. A directory is a specialized database that is primarily used for allowing a large number of people to quickly look up information. A directory is not intended to be primarily used as a tool for the organization and storage of data and is therefore optimized for information retrieval and not necessarily information storage. Directories lend to be designed for particular purposes and are not commonly used for general purpose searches. For example, the types of searches that a directory will handle are usually known ahead of time.  
         [0007]     A directory service is a computer application that allows for access to a directory. Directory services may conform to sets of standards such as, for example, the X.500 standard pertaining to electronic directory services. Users may interact with directories using standardized languages such as, for example, Directory Services Markup Language (DSML). DSML is a variant of Extensible Markup Language (XML), the human-readable communications language commonly used by web based applications for exchanging information between computers without regard to the computer&#39;s platfomm. DSML is specifically tailored for communicating directory information.  
         [0008]     While some directory services are local and only allow for use on a closed computer network, other directory services are global and allow for general access over an open computer network such as the Internet.  
         [0009]     Directory services may have redundant servers placed over a broad geographic area all of which cooperate to provide directory service. Such directory services are known as distributed directory services. The Internet Domain Name System (DNS) is an example of a global distributed directory service. The DNS allows computers connected to the internet to look up the numeric internet address from the corresponding internet domain name.  
         [0010]     LDAP, or Lightweight Directory Access Protocol, is a protocol for quickly and easily accessing directory services from across a computer network. LDAPs communicate using TCP/IP transfer services or similar transfer services making LDAPs well suited for use over the internet or private company intranets.  
         [0011]     An LDAP directory is often made up of objects. Each object may contain a number of attributes. Attributes may each be of a particular type and may each have one or more values conforming to that type. Examples of types of attributes include “cn” for common name, and “mail” for an email address. Other types of attributes include text, photos, URLs, pointers, binary data, etc. The correct syntax of the value is defined by the particular type of attribute. For example, an email address with the type “mail” may have a value of “bob@domainname.com”.  
         [0012]     Objects within LDAP directories can be hierarchically arranged for more efficient searching. For example, a hierarchical LDAP directory made up of domain name objects might begin with “.com”, “.org” and “.gov” objects at the top level of the hierarchy. Below each top level object may be a series of objects representing organizations, and within each of these organization objects may be a series of objects representing users. Hierarchical objects are commonly referred to as parent objects and child objects depending on their relationship to one another. For example, an object representing a printer may be the child of an object representing a computer in a hierarchical directory representing a computer network where the printer is connected to the computer. An object of any hierarchical generation may have one or more associated attributes. Attributes may be used to describe characteristics of the objects they are associated with. Each object and/or attribute may have one or more associated values.  
         [0013]      FIG. 1  is a block diagram showing an example of a hierarchical directory structure. Here the top level object (root object) is “organization.” This object has a string type and a value of “Computer Associates.” The child objects of the root object are called “office.” These objects have a string type and values of “R&amp;D,” “Sales,” “Legal,” and “Marketing.” The child objects of the office objects include “person” or “equipment” objects. These objects have a string type and have various values.  
         [0014]     LDAP directory services are commonly based on a client-server model. While one or more LDAP servers contain the LDAP data, a client may be launched by a person seeking to access LDAP directory data. The client may connect to the server and communicate the search criteria. The server may then communicate the search results to the client. The client may then communicate the search results to the user.  
         [0015]     One common example of a LDAP directory service is a service that resolves email addresses from names. Such directory services are commonly accessed by email clients that connect to email servers. In this example, the user can enter a contact&#39;s name to resolve the contact&#39;s email address.  
         [0016]     While directories, such as those utilizing LDAP, may be well suited for the quick execution of basic search queries, directories may not be able to handle some of the more complex search queries that may be commonly handled by general purpose relational databases. For example, many directories are unable to perform the common inner join (join) operation. The join operation retrieves all objects having two or more attributes, child objects and/or child object attributes being searched for. For example, given the example directory structure illustrated in  FIG. 1 , a join operation may be to retrieve a list of all offices that have a person named Alice and a photocopier.  
         [0017]     This information may still be retrieved from a directory without the use of a join operation; however, retrieval may require multiple searches. For example, a first search may be made to determine all offices with a person named Alice. With respect to the example directory structure of  FIG. 1 , the results would be R&amp;D and Sales. A second search would be to search R&amp;D for a photocopier and then to search Sales for a photocopier to determine if any of the offices with an Alice also have a photocopier. This second search may be executed using multiple searches or may be combined into one long and complex search, however the results would be comparable. This technique may be long and complicated, especially with a real-world directory which might contain thousands of entries.  
         [0018]     The need to conduct multiple searches to perform a common join operation may be a great shortcoming of directory technology. This shortcoming often frustrates newcomers to the field. Unfortunately, this shortcoming is largely intrinsic to directories. Redesign of directory technology to resolve this shortcoming in the general case may require major changes to the X.500/LDAP directory standards. Additionally, even if these standards were to be revised, most functioning directory architecture might not be capable of supporting the enhanced functionality.  
       SUMMARY  
       [0019]     A method for indexing a database of one or more objects having one or more attributes includes determining which of said one or more attributes should receive concatenation, concatenating those of said one or more attributes that have been determined to receive concatenation, and indexing said database with those of said one or more attributes that have been concatenated.  
         [0020]     A method for searching an indexed database of one or more objects having one or more attributes, includes receiving a query to search for an object having two or more particular attributes and searching for an object with an attribute that is a concatenation of said two or more particular attributes.  
         [0021]     A system for indexing a database of one or more objects having one or more attributes, includes a determining unit for determining which of said one or more attributes should receive concatenation, a concatenating unit for concatenating those of said one or more attributes that have been determined to receive concatenation, and an indexing unit for indexing said database with those of said one or more attributes that have been concatenated.  
         [0022]     A system for searching an indexed database of one or more objects having one or more attributes, includes a receiving unit for receiving a query to search for an object having two or more particular attributes, and a searching unit for searching for an object with an attribute that is a concatenation of said two or more particular attributes.  
         [0023]     A computer system includes a processor and a program storage device readable by the computer system, embodying a program of instructions executable by the processor to perform method steps for indexing a database of one or more objects having one or more attributes. The method includes determining which of said one or more attributes should receive concatenation, concatenating those of said one or more attributes that have been determined to receive concatenation, and indexing said database with those of said one or more attributes that have been concatenated.  
         [0024]     A computer system includes a processor and a program storage device readable by the computer system, embodying a program of instructions executable by the processor to perform method steps for arching an indexed database of one or more objects having one or more attributes. The method includes receiving a query to search for an object having two or more particular attributes, and searching for an object with an attribute that is a concatenation of said two or more particular attributes. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     A more complete appreciation of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
         [0026]      FIG. 1  is a block diagram showing an example directory structure;  
         [0027]      FIG. 2  is a block diagram showing an example of how the example directory structure of  FIG. 1  may be indexed according to an embodiment of the present disclosure;  
         [0028]      FIG. 3  is a flow chart illustrating an embodiment of the present disclosure; and  
         [0029]      FIG. 4  is a block diagram showing an example of a computer system capable of implementing the method and apparatus according to embodiments of the present disclosure. 
     
    
     DETAILED DESCRIPTION  
       [0030]     In describing the preferred embodiments of the present disclosure illustrated in the drawings, specific terminology is employed for sake of clarity. However, the present disclosure is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner.  
         [0031]     Embodiments of the present disclosure seek to allow for the application of complex search operations, for example, the join operation, with respect to directories, for example LDAP directories.  
         [0032]     Because directories tend to be used as special purpose data stores, rather than for storing and manipulating generic data, the types of searches that a user might request may be predictable. For example, the example directory  11  defining the Organization may be searched for the names of people and types of equipment located in each office. Embodiments of the present disclosure seek to utilize this knowledge to prepare the directory for the anticipated types of searches.  
         [0033]     For example, object data within the directory may be concatenated and indexed. These indexes may then be added as attributes of each office object in the directory. Concatenation is the combining of one or more of the possible combinations of object attributes that a user might issue a search for. Object attributes may be, for example, attributes associated with child objects of the object. For example, anticipating that a user might issue a search for offices with a particular person and a particular equipment item, each combination of a person and an equipment item may be concatenated. For example, with respect to example directory  11 , within the R&amp;D office, no attributes need be concatenated because there are no possible combinations of a particular person and a particular equipment item. Within the Sales office, Alice and photocopier may be concatenated and Dennis and photocopier may be concatenated because they represent the various combinations of a particular person and a particular equipment item. Accordingly, in the Legal office, Bob and photocopier may be concatenated and Erik and photocopier may be concatenated. In the Marketing office, Fred and photocopier may be concatenated and George and photocopier may be concatenated.  
         [0034]     To determine which object attributes should be concatenated, a type of search may be anticipated. In addition to the type of search described above, there are other possible searches that may be anticipated. For example it may be anticipated that a user might issue a search for an office that includes two particular people. Where such a search is anticipated, each possible combination of two people within each office object may be concatenated.  
         [0035]     Concatenation is not limited to combining only two object attributes. Any number of object attributes may be concatenated. For example, where it is anticipated that a user might issue a search for an office that includes three particular people, every possible combination of three people within each office object may be concatenated.  
         [0036]     There are many possible methods by which object attributes may be concatenated. For example, attributes being concatenated may be combined as a single word with a separator character between them. This separator character may be a character that is not likely to appear within the data. For example, the caret character (“{circumflex over ( )}”) may be a good character to use for directories that store data in English. Other examples of good separator characters may include the dollar sign character (“$”) and the null character (ASCII value 0). For illustrative purposes, the examples illustrated in this disclosure will use the caret character as the separator character.  
         [0037]     Where a separator character has been chosen, for example the caret character has been chosen, object attributes may be concatenated by combining them as a single word with the caret character between them. For example, concatenating Alice and photocopier would produce “Alice{circumflex over ( )}photocopier”.  
         [0038]     Concatenated attributes may be used as an index and these indexes may be added as attributes of each object in the directory being searched for.  FIG. 2  is a block diagram showing an example of how the example directory  11  of  FIG. 1  may be indexed according to an embodiment of the present disclosure. In this example  21 , the example directory  11  has been indexed in anticipation of a search that would request all office objects with a particular person and a particular equipment item. In this example  21 , the separation character selected is the caret.  
         [0039]     For each office each possible combination of a person and equipment is identified. In the R&amp;D office, because there is no equipment, there are no such combinations. In the Sales office, the possible combinations include “Alice and photocopier” and “Dennis and photocopier.” These combinations may be concatenated to produce “Alice{circumflex over ( )}photocopier” and “Dennis{circumflex over ( )}photocopier” indexes. These indexes may then be added as attributes of the R&amp;D office object.  
         [0040]     A directory may be indexed, according to embodiments of the present disclosure, at any time prior to a user executing a search. For example, the directory may be indexed as each object of the directory is created or all at once after the directory has been created. The indexing of directories according to embodiments of the present disclosure, may be carried out manually, for example, by a user entering in objects into the directory, or automatically using an application designed to index according to the preset disclosure.  
         [0041]     An indexed directory may be easily searched using complex search operations, for example the join operation. When a search is requested, for example, a search for all offices containing an Alice and a photocopier, the directory is searched for an “Alice{circumflex over ( )}photocopier” attribute. Where such a combination exists, such an index will be found as an attribute. The objects where the index was found may then be returned as results of the search. For example, in the example directory  11   21 , “Alice{circumflex over ( )}photocopier” may be found at the Sales office.  
         [0042]     According to an embodiment of the present disclosure, a user interface may be used to convert a complex search request (query), for example a query requesting a join operation, into a search for a concatenated index. According to another embodiment of the present disclosure, a user wishing to conduct a search may manually initiate a search for a concatenated index.  
         [0043]     The order in which object attributes are concatenated may affect the success of the search. For example, a search for “photocopier{circumflex over ( )}Alice” may not return the desired results. According to one embodiment of the present disclosure, a convention can be established whereby the concatenation order is predetermined. For example, object attributes may be concatenated in alphabetical order or according to another predetermined order. Alternatively, a search may include all possible orders. For example, a search may search for both “Alice{circumflex over ( )}photocopier” and “photocopier{circumflex over ( )}Alice”. Alternatively, when the object is indexed, it may be indexed multiple times, once for each possible order. These techniques may be implemented manually or automatically, for example by a directory client.  
         [0044]      FIG. 3  is a flow chart illustrating an embodiment of the present disclosure. According to this embodiment, the first step is to determine which object attributes should be concatenated (Step S 31 ). Next, the object attributes determined to be concatenated should be concatenated using a predetermined separator character (Step S 32 ). The directory should then be indexed by adding the concatenated objects as attributes of objects in the directory (Step S 33 ). The indexed directory may then be searched (Step S 34 ).  
         [0045]      FIG. 4  is a block diagram showing an example of a computer system which may implement the method and system of the present disclosure. The system and method of the present disclosure may be implemented in the form of a software application running on a computer system, for example, a mainframe, personal computer (PC), handheld computer, server, etc. The software application may be stored on a recording media locally accessible by the computer system and accessible via a hard wired or wireless connection to a network, for example, a local area network, or the Internet.  
         [0046]     The computer system referred to generally as system  1000  may include, for example, a central processing unit (CPU)  1001 , random access memory (RAM)  1004 , a printer interface  1010 , a display unit  1011 , a local area network (LAN) data transmission controller  1005 , a LAN interface  1006 , a network controller  1003 , an internal buss  1002 , and one or more input devices  1009 , for example, a keyboard, mouse etc. As shown, the system  1000  may be connected to a data storage device, for example, a hard disk,  1008  via a link  1002 .  
         [0047]     The above specific embodiments are illustrative, and many variations can be introduced on these embodiments without departing from the spirit of the disclosure or from the scope of the appended claims. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.