Mastering Hibernate

SQL/DDL modifier

In this section, we will discuss annotations that modify the SQL or the DDL used by Hibernate to perform a query or generate schema objects. The DDL modifying annotations are important if you use Hibernate to generate your tables.

@Check

Using the @Check Hibernate annotation, you can add the CHECK constraints to your table. The constraint defined in the @Check annotation uses the syntax that is supported by the database of your choice.

The following listing adds a constraint to the price column:

@Entity
@Check(constraints = "price >= 0")
public class Item {
  @Id
  @GeneratedValue
  private long id;
  private String description;
  private double price;
  // setters and getters
}

The DDL generated using PostgreSQL, is shown here:

 create table Item ...