On Tue, 6 Apr 2004, Robert Treat wrote: > Trying to come up with the proper syntax to meet the following criteria: > > create table foo (bar integer, baz boolean UNIQUE (bar, baz = true)); > > note the above syntax is not correct, but should demonstrate what i'm > trying to do; I want to add a unique constraint such that we only allow > one case of bar and baz = true... i can have unlimited bar and baz = > false, and there can be multiple bar and baz = true if the bars are > different... did some doc reading and mail list searching but a valid > syntax for this seems to be escaping me... > > btw I'm pretty sure I could do this with an external trigger, but am > wondering about a constraint oriented approach
You can't precisely with a constraint (AFAIR sql is marginally limited in that way at least in 92 and 99), but you should be able to do it with a partial unique index something like create unique index foo_i on foo(bar) where baz is true; ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
