postgresql - Does a Postgres UNIQUE constraint imply an index?

Question

When adding a unique constraint to a Postgres table does that imply that an index has also been added to that table?

Meaning, if I add a UNIQUE constraint on a text column, does that text column now have an index or does an index have to be added separately?

Answer 1

Yes.
UNIQUE constraints are implemented using a unique B-tree index in Postgres.

See:

• How does PostgreSQL enforce the UNIQUE constraint / what type of index does it use?