ALTER SEQUENCEは、シーケンス(順序)を変更するSQL文です。順序の初期値、増分値、最大値、最小値、および順序のサイクルを変更できます。
ALTER SEQUENCE sequence [START WITH start] [INCREMENT BY inc] [MINVALUE min] [MAXVALUE max] [CYCLE]
[RESTART]
SQL> ALTER SEQUENCE example START WITH 2;
SQL> SELECT example.NEXTVAL FROM DUAL;
NEXTVAL
-------
2
SQL> SELECT example.NEXTVAL FROM DUAL;
NEXTVAL
-------
3
SQL> ALTER SEQUENCE example INCREMENT BY 2;
SQL> SELECT example.NEXTVAL FROM DUAL;
NEXTVAL
-------
1
SQL> SELECT example.NEXTVAL FROM DUAL;
NEXTVAL
-------
3
SQL> ALTER SEQUENCE example MINVALUE 0;
SQL> ALTER SEQUENCE example MAXVALUE 999;
SQL> ALTER SEQUENCE example CYCLE;
SQL> ALTER SEQUENCE example RESTART;