How to specify a Primary Key on @ElementCollection



So, there is that behavior with innodb that can cause problem if some tables lack of primary key.

So with Hibernate, I am looking for a key to specifies a primary key on a @ElementCollection table with a Set as the underling data structure.

I found a way to have a primary key with a map, but it is kind of weird because I do not need a map.

I also found an answer related to @Embeddable, but I do not need that kind of complexities. I am using a Set or Set as the data structure in my entities.

Any idea how to achieve that?

Answer

If you use a Set and make the element Column be not null, then hibernate will make a primary key with the join column and element column.

Example:

@Column(name = "STRINGS", nullable = false)
@ElementCollection
private Set<String> strings;


Source: stackoverflow