Note: At present, this section is just taken from PostgreSQL documentation and is subject to revision for Postgres-XC.
DROP SEQUENCE removes sequence number generators. A sequence can only be dropped by its owner or a superuser.
Do not throw an error if the sequence does not exist. A notice is issued in this case.
The name (optionally schema-qualified) of a sequence.
Automatically drop objects that depend on the sequence.
Refuse to drop the sequence if any objects depend on it. This is the default.