Comment 2 for bug 1569884

Steve,

That is close, but will stop one from deleting two parts with the same label. You're proposal in the description is actually closer, but can't be done with a CONSTRAINT directly. Instead, we need a partial unique index. Something like:

ALTER TABLE biblio.monograph_part DROP CONSTRAINT "record_label_unique";
CREATE INDEX CONCURRENTLY record_label_unique_idx ON biblio.monograph_part (record, label) WHERE deleted = FALSE;