@UniqueConstraint超过两列

Question

In my Spring/hibernate project I'm using uniqueConstraints = {@UniqueConstraint(columnNames={"ID_A", "ID_B"})} to validate a unique combination of columns in a table. This works fine when I only have two columns.

However when I want to add a third column ID_C to the constraint it no longer works.

1. Does @UniqueConstraint only allow for two columns?
2. If yes, then how would I validate the unique combination for more than two columns?

Thank you for the help, /D

Edit: What I mean by "it no longer works" is that no exception is thrown when I add a new entry to the table. With two columns it throws an ConstraintViolationException .

Answer 1

Adding UniqueConstraint alone to entity does not perform any validation. As said in the linked documentation, it gives instructions that are used in database schema generation:

Specifies that a unique constraint is to be included in the generated DDL for a primary or secondary table.

Now you have two options left:

1. Let Hibernate to generate database schema
2. Drop old constraint and add new by using SQL as usually.