Customized naming of columns in JPA relationships

Question

When I make relationsships with JPA using hibernate, some terrible long and ackward column names are generated.
Eg. I have the following actionPlan_actionPlanPK, which means that the column actionPlan is a FK that points to actionPlanPK.
To make it look just a little bit more neat in the DB I would like if I could give it a name myself, preferably just the name it has in the entity class that owns the relationship.

Is this possible with JPA?

Answer 1

Yes. It is possible to specify your own name for a column if you are not satisfied with the default names. For instance in the class with the reference to the ActionPlan you can specify:

@ManyToOne
@JoinColumn(name="actionplanId")
public ActionPlan getActionPlan(){

}

And thus, the column name will be "actionplanid".

Answer 2

This capability is part of the JPA specification and allows for the naming of many of your database structures in the annotations. These include:

Naming your table as follows:

@Entity
@Table(name="better_table_name")
public class MyConvolutedClassName {
}

Naming your columns as follows:

@Column(name="better_column_name")
private Date myConvolutedDateColumn;

Naming your columns that are part of a relationship:

@ManyToOne
@JoinColumn(name="better_join_column_name")
private ClassName otherModelClass;

There's a great (though not quite up-to-date) cheatsheet for EJB 3.0 annotations (which includes JPA) available at http://www.fnogol.de/media/ejb3.0-anno-cheat-1.2.pdf.