> > I was bored and thought "how hard could it be?", and a few hours' > hacking later, I have something that seems to work. It doesn't do IF > NOT EXISTS yet, and the error messaging could do with some improvement, > and there are no docs. The patch is attached, as well as at > https://github.com/ilmari/postgres/commit/enum-alter-value
Actually you still miss a "DROP VALUE" action. Also please make sure this also works when altering an existing enum within a new transaction - otherwise it does not really make sense (Usually someone wants to alter existing enums, not ones that have just been created).
As a result a script like this should pass without problems:
-- ### script start
CREATE TYPE bogus AS ENUM('dog');
-- TEST 1:
BEGIN;
ALTER TYPE bogus ADD VALUE 'cat'; -- fails in 9.5 because of the transaction but should work in future
COMMIT;
-- TEST 2:
BEGIN;
ALTER TYPE bogus RENAME TO bogon;
ALTER TYPE bogon ADD VALUE 'horse'; -- fails in 9.5 because of the transaction but should work in future
COMMIT;
-- TEST 3:
BEGIN;
ALTER TYPE bogon ALTER VALUE 'dog' TO 'pig'; -- not implemented in 9.5 but should work in future
ROLLBACK;
-- TEST 4:
BEGIN;
ALTER TYPE bogon DROP VALUE 'cat'; -- not implemented in 9.5 but should work in future
ROLLBACK;
-- ### script end
End result of enum "bogon" (which was named "bogus" at the beginning of the script):