Persist Grails Domains *ONLY* after Relationship built - grails

Question

I'm wondering if its possible to create a grails domain object, but only have it persist on command as opposed as when we do operations on it.
To be more precise, this is what I have to do now:
Foo foo = new Foo(name:"asdf")
Bar bar = new Bar(name:"gzxj")
bar.save() // persist here
foo.save() // persist here
foo.addToBars(bar) // now I have to build the relationship
What I want:
Foo foo = new Foo(name:"asdf")
Bar bar = new Bar(name:"gzxj")
foo.addToBars(bar) // just build the relationship
bar.save() // would be great to ignore this step
foo.save() // can I now atomically build both objects and create the relationships?
My impressions is that the latter would be far faster if there are many relationships to associate. Am I really just wanting NoSQL here?

Answer 1

Depending on how you have your relationships set up, this is entirely possible. It really has nothing to do with what database you have implemented.
Parent class
class Foo {
String name
static hasMany = [bars: Bar]
}
Child class
class Bar {
String name
Foo foo //optional back reference
static belongsTo = Foo
}
Execution
Foo foo = new Foo(name: 'a')
Bar bar = new Bar(name: 'b')
foo.addToBars(bar)
foo.save()
//or even more terse
Foo foo = new Foo(name: 'c')
foo.addToBars(new Bar(name: 'd'))
foo.save()
The key is the belongsTo which defaults to a cascade of all. This can be explicitly set as well:
class Foo {
String name
static hasMany = [bars: Bar]
static mapping = {
bars cascade: 'all'
}
}