Hi,
I have a problem.
Let's say I have the following table:
CREATE
TABLE rekl_element(
id serial PRIMARY KEY,
active boolean NOT NULL DEFAULT 'y',
num int4 NOT NULL,
text varchar(10)
);Now I want that "num" column is "unique" but only for those columns that have active='y'. For the columns that have active='f' I don't care if num is unique or not. I'm asking this because num will be doubled some times.
How can I write a constraint, trigger function... etc to check this?
Thanks in advance.
Andy.