[20190530]ORACLE 18c - ALTER SEQUENCE RESTART.txt

[20190530]ORACLE 18c - ALTER SEQUENCE RESTART.txt

--//以前遇到要重置或者調整seq比較麻煩,我有時候採用比較粗暴的方式就是刪除重建.

--//18c提供方式重置,自己測試看看.

1.環境:

SYSTEM@xxxxxx> select BANNER from v$version;

BANNER

----------------------------------------------------------------------

Oracle Database 18c Enterprise Edition Release 18.0.0.0.0 - Production

SYSTEM@xxxxxx> CREATE SEQUENCE Seq1 START WITH 1 INCREMENT BY 1 MINVALUE 1 MAXVALUE 9999;

Sequence created.

SYSTEM@xxxxxx> SELECT Seq1.nextval FROM dual;

   NEXTVAL

----------

         1

SYSTEM@xxxxxx> SELECT Seq1.nextval FROM dual;

   NEXTVAL

----------

         2

--//批次執行如下:

$ seq 500 | xargs -I{}  echo select seq1.nextval from  dual\; | rlsql system/xxxx@xxxxxx

SYSTEM@xxxxxx> SELECT Seq1.nextval FROM dual;

   NEXTVAL

----------

       503

--//現在已經到503.

SYSTEM@xxxxxx> ALTER SEQUENCE Seq1 RESTART;

Sequence altered.

SYSTEM@xxxxxx> SELECT Seq1.nextval FROM dual;

   NEXTVAL

----------

         1

--//現在回到1的位置.還可以這樣執行:

SYSTEM@xxxxxx> ALTER SEQUENCE Seq1 RESTART START WITH 1500;

Sequence altered.

SYSTEM@xxxxxx> SELECT Seq1.nextval FROM dual;

   NEXTVAL

----------

      1500