Thanks, I should have been more specific, these are unique constraints I am concerned about: so yeah, creating an index on a set of columns where there's a unique constraint is redundant, correct?
Are constraints also indexes, or would you want an additional index on top of a constraint if you wanted that column/combo indexed?
No, having a constraint does not imply that an index exists. However, the enforcement of a "unique" constraint is implemented by auto-creating a unique index.