Greg Stark <st...@mit.edu> wrote: > Only IMMUTABLE functions can be used in CHECK constraints. > It's a feature that expressions including subqueries are > automatically detected as not being immutable and automatically > barred. It doesn't look like that to me: test=# create function xxx() returns text volatile language plpgsql as $$ begin return 'xxx'; end; $$; CREATE FUNCTION test=# create table x (id int not null primary key, val text check (val <> xxx())); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "x_pkey" for table "x" CREATE TABLE test=# insert into x values (1, 'aaa'); INSERT 0 1 test=# insert into x values (2, 'xxx'); ERROR: new row for relation "x" violates check constraint "x_val_check" DETAIL: Failing row contains (2, xxx). Perhaps you're thinking of function usage in index definitions?
A CHECK constraint using a volatile function is potentially valid and useful, IMO. Think about a column which is supposed to record the moment of an event which has occurred. It could make sense to ensure that the timestamptz value is < now(); On the other hand, an index entry based on now() is clearly a problem. Otherwise I agree with your response -- this is clearly *not* a bug. -Kevin -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
