To only partially answer my own question, I can have OpenJPA generate a unique
constraint when I add something like:
@ManyToMany
@JoinTable(joinColumns = { @JoinColumn(name = "CONTACT_ID") },
inverseJoinColumns = { @JoinColumn(name = "MAILINGLISTS_ID") },
uniqueConstraints = { @UniqueConstraint(columnNames = {
"CONTACT_ID", "MAILINGLISTS_ID" }) })
private List<MailingList> mailingLists = new ArrayList<MailingList>();
Here I used the default column names that OpenJPA generates for me.
However this is not a primary key. Plus I think it's rather ugly having to add
boiler plate like this; isn't JPA intended to minimize having to write
boilerplate code?
-----Oorspronkelijk bericht-----
Van: Henno Vermeulen [mailto:[email protected]]
Verzonden: donderdag 20 september 2012 16:37
Aan: '[email protected]'
Onderwerp: no primary key on generated join table
When I use @ManyToMany on a List or Set and let OpenJPA generate my database
schema, it creates a join table with two foreign key columns that allows
duplicates.
Is there a way to let OpenJPA generate a compound primary key on both the
foreign key columns or should I manually add these in the database?
Or is not a problem when a join table has no primary key?
