Re: plpgsql/rule question

"Ed L." <pgsql@bluepolka.net> writes:
> For example, if I have the following table:

>     create table foo(id serial, msg varchar)

> Is it possible to distinguish within plpgsql between these two queries?

>     insert into foo (msg) values ('Hello')
>     insert into foo (id, msg) values (NULL, 'Hello')

Well, yes, because the default value in the former case will not be
NULL.  But in general a trigger function cannot tell whether a field
value that happens to equal the default was explicitly specified or
defaulted.  All it can see is the proposed field value; not how that
value was arrived at.

            regards, tom lane