Question

I have a domain class:

class Author {
    String name
    static hasMany = [superFantasticAndAwesomeBooks: Book, superBadAndUltraBoringBooks: Book]
}

This is all nice when using the in-memory database, however, when running on Oracle the Book collections are modeled in a join table which cannot be created because the column names are too long.

So, then I tried specifying the join table properties:

static mapping = {
    superFantasticAndAwesomeBooks joinTable: [key: awesomeBooks]
    superBadAndUltraBoringBooks joinTable: [key: boringBooks]
}

The problem (which doesn’t happen if joinTable isn’t specified) is that the join table is created where columns correspoinding to awesomeBooks and boringBooks are NOT NULL (they need to be nullable because a Book will be an awesomeBook or a boringBook)

Is there any way to configure joinTable to allow NULL columns?

Answer 1

I just ended up using 2 join tables:

static mapping = {
    superFantasticAndAwesomeBooks joinTable: [name: 'awesomeBooks', key: 'book_id']
    superBadAndUltraBoringBooks joinTable: [name: 'boringBooks', key: 'book_id']
}