Question

I’m having an Entity that contains a Set like the following:

@ElementCollection
Set<String> branches;

Now what Hibernate does, is creating a table project_branches (project_id | branches) and adding a unique constraint on branches. Is there any way to tell hibernate that the unique constraint should involve both, project_id and branches?

I could not find an answer to this question, though I think I’m not the first with this problem… Thanks

Answer 1

This is dependent on the columns involved in the mapping.

There in one other configuration. Please consider adding an UniqueConstraint annotation at entity level e.g. below:

  @Table(name="project_branches",
    uniqueConstraints = {@UniqueConstraint(columnNames={"project_id", "branches"})}
  )

EDIT: Try using @CollectionTable annotation.

 @ElementCollection
 @CollectionTable(
    name="project_branches",
    joinColumns=@JoinColumn(name="branches"),
    uniqueConstraints = {@UniqueConstraint(columnNames={"project_id", "branches"})}
  )
  Set<String> branches;