Creating persistent entities

In this recipe we look at how Spring Roo simplifies the creation of JPA entities using the entity and field commands. In this recipe we'll create a Flight JPA entity which has a composite primary key. Refer to the Creating a many-to-one relationship between entities recipe of Chapter 3, Advanced JPA Support in Spring Roo to see how to create persistent entities with surrogate keys.

The following figure shows the attributes of the Flight entity and its composite primary key (FlightKey):

Getting ready

Exit the Roo shell and delete the contents of the C:\roo-cookbook\ch02-recipes directory.

Execute the ch02_jpa_setup.roo script. It creates a flight-app Roo project and sets up Hibernate as the persistence provider using the persistence setup command. If you are using a different database than MySQL or your connection settings are different from what is specified in the script, then modify the script accordingly.

Start the Roo shell from the C:\roo-cookbook\ch02-recipes...