On 7/15/05, Andrus <eetasoft@xxxxxxxxx> wrote: > CREATE TABLE test( col1 CHAR NOT NULL, col2 CHAR, > UNIQUE (col1, col2) ); > INSERT INTO test VALUES ( '1', NULL ); > INSERT INTO test VALUES ( '1', NULL ); > does NOT cause error! > > How to create constraint so that NULL values are treated equal and second > insert is rejected ? Please read: http://www.postgresql.org/docs/8.0/interactive/indexes-unique.html ...or this list archives. In short: NULL is not equal to NULL. NULL is a state, not a value. Regards, Dawid ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
