Grails Many to one Relationship deletion

Question

class First {
    String text
    Second second

    static constraints = {
    }
}

class Second {
    String name

    static constraints = {
    }
}

When I delete Second class object, I got an error like this:

Cannot delete or update a parent row: a foreign key constraint fails.

I want to delete only the instance of Second inside First.

Answer 1

You have to remove the association of Second from First (aka FK constraint) and then will be able to delete Second .

first.second = null
second.delete()

Refer removeFrom for more details when one-many & many-many relations are used.