DROP SEQUENCE — remove a sequence
DROP SEQUENCE removes sequence number generators. A sequence can only be dropped by its owner or a superuser.
IF EXISTS
Do not throw an error if the sequence does not exist. A notice is issued in this case.
name
The name (optionally schema-qualified) of a sequence.
CASCADE
Automatically drop objects that depend on the sequence, and in turn all objects that depend on those objects (see Section 5.14).RESTRICT
Refuse to drop the sequence if any objects depend on it. This is the default.
要移除序列物件：
DROP SEQUENCE 符合 SQL 標準，但標準僅允許每個指令移除一個序列，包含除了 IF EXISTS 選項（它是 PostgreSQL 加入的功能）外的部份。