Osama's Weblog

I was wondering what if I have to create a one to one relationship between two objects. There is no declarative way where we can specify a one to one relationship between two objects.

We can write a trigger to enforce a one to one relationship between two objects. The trigger can be written on the child object that validates if there is any other record with same Parent record ID. If found then instead of inserting the record, it gives an alert.

The trigger will generate a list of child objects with specified parent ID. If the list’s length that is retrieved is greater than one, it will generate an alert.

List<ChildObject> co = [select name from ChildObject where parentId = ParentId]
If  (co.Size() < 2)
{
//insert
}
else
//generate alert