In PG:
I made a user table that includes unique emails, but later decided that emails should not be unique. I pushed changes to make my email field non-unique (I use
I bet that "unique_users_email" is actually the name of a unique index rather than a constraint. Try:
DROP INDEX "unique_users_email";
Recent versions of psql should tell you the difference between a unique index and a unique constraint when looking at the \d description of a table.
\d