Lesson 1.5: Add primary keys to the entities and configure the runtime database connection
In this lesson you will learn how to add primary keys and named queries to the entities that you generated in the previous lesson. You will also learn how to configure a runtime connection to the Derby database.
Before you begin, complete Lesson 1.4: Create entity beans from the database tables.
Configure the entity beans
JPA entities must include an @Id annotation to define the entity's primary key. The JPA Tools can add the required primary key annotation for you.
Perform the following steps to configure the entity beans:
- In the Enterprise Explorer, right-click on one of the entity beans
- Employee.java or Department.java - and select
JPA Tools | Configure JPA Entities.
- On the Configure JPA Entities Page, ensure that both entities are
selected. Click
Next.
- On the Tasks Page, click
Department. Ensure that
Primary Key is selected, and then select
deptno as the primary key.
- On the same page (Tasks), click
Employee. Select
empno as the primary key.
- Click
Finish. The Configure
JPA Entities wizard adds the primary key annotations to the entities.
The Set up Connections for Deployment wizard opens.
Configure the runtime connection
Perform the following steps to configure the runtime connection to the Derby database:
- If the Set up connections for deployment wizard did not automatically
open, right-click the project in the Package Explorer and click
JPA Tools | Configure Project for JDBC deployment.
- For Schema, select
SAMP. Leave all other selections at their defaults and click OK.
Lesson checkpoint
You have completed Lesson 1.5. In this lesson, you learned how to add primary keys to your JPA entity beans. You also learned how to configure a runtime connection to a database.