Re: Trigger function is not called

Klint Gore <kgore4@une.edu.au> writes:
> ...  With the not null definition in the domain, this
> blows up before anything else has a chance.

Right.  Forming the proposed row-to-insert involves coercing the data to
the correct data types, and for domain types enforcing the domain
constraints is seen as part of that.  So you can't use a trigger to
clean up problems that violate the column's datatype definition.

However, constraints associated with the *table* (such as a NOT NULL
column constraint in the table definition) are enforced only after the
before-trigger(s) fire.  So you could use a table constraint to backstop
something you're expecting a trigger to enforce.

This difference is probably what's confusing Bill, and I didn't help any
by giving wrong information about it just now.  Sorry again.

            regards, tom lane