Dropping sequences
Use DROP SEQUENCE to remove a named sequence.
	Use 
DROP SEQUENCE to remove a named sequence. For example:
=> DROP SEQUENCE my_sequence;
You cannot drop a sequence if one of the following conditions is true:
- 
Other objects depend on the sequence. DROP SEQUENCEdoes not support cascade operations.
- 
A column's DEFAULTexpression references the sequence. Before dropping the sequence, you must remove all column references to it.