Java Reference
In-Depth Information
Creating entity beans from tables
In this section, we create EJB 3.0 entity beans from database tables. Right-click on
the Model project node in the Application navigator and select New . In the New
Gallery window, select Business Tier|EJB in Categories and Entities from Tables
in Items . Click on OK . Next, we define the Persistence Unit for the entity beans. A
Persistence Unit defines a data source, and other database persistence properties
for creating and persisting entity beans. A persistence unit is defined in the META-
INF/persistence.xml configuration file. Click on New . In the New Persistence
Unit window, specify a persistence unit Name ( em for example). Specify a JTA
Datasource Name . Earlier we created a connection OracleDBConnection . A data
source with JNDI name jdbc/OracleDBConnectionDS gets created by default
when the connection is created. The data source name is of the format jdbc/
ConnectionNameDS , in which ConnectionName is the variable; the connection
name is what changes based on the database connection defined in JDeveloper.
Specify jdbc/OracleDBConnectionDS as the JTA Datasource Name . The TopLink/
EclipseLink is used as the JPA persistence provider. Select the Default Database
Platform and the Server Platform as WebLogic 10 . Click on OK . A new Persistence
Unit ( em ) gets defined. Click on Next . In the Type of Connection window, a
developer may select from an Online Database Connection , an Offline Database
Connection , or a Application Server Database Connection . Select Online Database
Connection and click on Next .
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