On 2009-01-21, Brent Wood <b.wood@xxxxxxxxxx> wrote: > Hi, > > I have a table with a column of ID's (integer), these are unique > except where they = -1 (column 1) > I have a partial unique index where the value is not -1 to enforce this. > I want to use this column as a foreign key on a column in another table > (column 2), but cannot without a full unique index. a full unique index is easy use an expression that's null for -1. create unique index foobar on foo( ( case fee when -1 then null else fee end ) ); > Is there any way to add an equivalent constraint to a foreign key which > restricts entries in column 2 to values in column 1? unfortunately expressions don't seem to be allowed for foreign key constraints you could add an auxillary column and create a rule, or trigger to keep it updated. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
