Chapter 14 Working with Java
Object to relational mapping allows you to generate objects from an Object-Oriented Model into a Physical Data Model. It is the process of having classes, attributes and operations mapped to relational tables, columns and queries by using DBMS compliant codes for OOM objects generated into the PDM. The purpose is to set up object storage in a relational database.
Object to relational mapping is used in the current context to generate an O/R mapping descriptor for EJBs CMP or EJB BMP implementation in an application server. You must define an O/R mapping description file format to be used for EJB implementation in your application server.
For more information on how to define the O/R mapping description file, see section Defining O/R mapping, in chapter Working with Object-Oriented Models.
It is necessary to add a specific extended model definition tied to a server so that the server understands the format of the O/R mapping description file. You may import the extended model definition at any time, even before the creation of your EJBs. You can use the following extended model definition samples located in the Resource Files folder of PowerDesigner:
For more information on how to import extended model definitions, see section Choosing a target application server.
It is recommended to read the appropriate technical document located in the Printable Docs directory of your installation, prior to using the extended model definition file.
Based on these samples, you can create your own extended model definition tied to the application server of your choice. Verify that the version of EJB supported in your application server is EJB 2.0.
You can find technical documents on other model extensions that are available for PowerDesigner. They are located in the Printable Docs directory of your installation.
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