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User Guide
The information contained in this section applies to IBM WebSphere Commerce Version 7.0.0.9 and Feautre Pack 8. The documentation also applies to all subsequent releases and modifications until otherwise indicated in new editions.
Developing
The topics in the Developing section describe tasks performed by an application developer.
Web services and WebSphere Commerce
A web service is an interface that describes a collection of operations that are accessible through the network by using standardized XML messaging.
Data service layer
The data service layer (DSL) provides an abstraction layer for data access that is independent of the physical schema.
Data service layer query processing
The data service layer uses the different sections of the query template file to control how the query is run.
Query template file
The query template file is a mechanism by which you can easily map a query on your logical model to one or more SQL statements. The SQL assets are kept in separate files, which are isolated from the runtime Java code. This template helps database administrators and programmers to locate and analyze SQL statements. Additionally, changes to SQL that are used for queries do not require recompiling Java code. Also, the addition of new columns into existing tables might not require changing SQL statements that use those tables. Column information is separated out in the SYMBOL_DEFINITIONS section.
Graph composer
In the query template file, an optional graph composer Java class can be specified in the ENTITY section within the PROFILE block. This Java class allows you to augment the final graph of physical SDOs. It can perform data aggregation from other sources and can merge multiple graphs of physical SDOs into a single graph if there is more than one associated SQL statement defined in the profile for the base table object.

Graph composer

In the query template file, an optional graph composer Java class can be specified in the ENTITY section within the PROFILE block. This Java class allows you to augment the final graph of physical SDOs. It can perform data aggregation from other sources and can merge multiple graphs of physical SDOs into a single graph if there is more than one associated SQL statement defined in the profile for the base table object.

The graph composer is needed for two-step queries that use multiple association SQL statements. You need to implement your own graph composer only if the result sets of the association SQL statements retrieve identical records from tables other than the base table.

If specified, the graph composer must subclass from the com.ibm.commerce.foundation.server.services.dataaccess.GraphComposer abstract class and implement the abstract composeGraph() method.

For example:

BEGIN_PROFILE 
	name=profileName1

	BEGIN_ENTITY 
	  entity_table=CATENTRY 

<!-- must subclass from com.ibm.commerce.foundation.server.services.dataaccess.GraphComposer -->
<!-- used to compose the final graph --> 
<!-- if more than one associated SQL statement defined -->
	  className=com.my.GraphComposer

   associated_sql_statement=CatEntryWithDescription
   associated_sql_statement=CatEntryWithProperty
 END_ENTITY
END_PROFILE