Search for Child Objects with No Child Objects

Question

Backendless documentation has an example about querying related objects; Phonebook (parent) has child Contact (child) has child Address (grandchild) (phonebook->contact->address).

You can use "is null" to find parent objects with no child object

Contact is null

But when you try to find child objects with no grandchild objects. The query fails with "invalid where clause."

Contact.Address is null

Answer 1

I developed this solution, which checks to see if the grandchild object system generated field is null.

Contact.Address.created is null //Contact has no Address child object

Contact.Address.created is not null //Contact has Address child object