Develop > Business logic layer
Work with the data service layer
You can customize the data service layer to create and modify schemas and queries.
- Extend the WebSphere Commerce schema using the data service layer
You can extend the existing schema to support customization. These extensions include changing the physical database schema, generating the object-relational metadata and physical SDOs, and using query templates to retrieve the new information.
- Create a query
Query templates are used to define queries in the Data Service Layer. The template file maps queries on the logical model (XPath queries) to templated SQL statements. These templates are used to generate the actual SQL queries. These are invoked by the Data Service Layer to access the database. Each query is analogous to an EJB finder method.
- Deploy customizations made using the BOD command framework and the data service layer
Deploying customizations to the data service layer to a production server is handled using WebSphere Application Server deployment.
- Enable optimistic concurrency control for custom tables
Most WebSphere Commerce tables use optimistic locking for database performance reasons. A similar functionality is provided for the data service layer, called optimistic concurrency control. Optimistic concurrency control can slightly decrease performance but allows for much greater concurrency during heavy database load, because it allows for a reduction in the transaction isolation level, reducing locking.
- Techniques for improving the performance of SQL queries under workspaces in the Data Service Layer
SQL queries under workspaces can suffer performance issues. Performance degradation often occurs if the database is not being properly maintained or if queries can be rewritten more efficiently. In addition to making sure that the database is properly maintained, there are several techniques that can help improve the performance of SQL queries under workspaces. While no single technique yields significant results, a combination of several techniques can help achieve considerable performance improvements in many applications.
Related concepts
Overview of the get-data-config.xml file