MySQL5的异常处理

核心提示： CREATE PROCEDURE p23 ()BEGINDECLARE CONTINUE HANDLERFOR SQLSTATE '23000' SET @x2 = 1;SET @x = 1;INSERT INTO t4 VALUES (1);SET @x = 2; <

CREATE PROCEDURE p23 ()

BEGIN

DECLARE CONTINUE HANDLER

FOR SQLSTATE '23000' SET @x2 = 1;

SET @x = 1;

INSERT INTO t4 VALUES (1);

SET @x = 2; <--

INSERT INTO t4 VALUES (1);

SET @x = 3;

END;//

然后@x的值变为2。
6. DECLARE CONTINUE HANDLER example

CREATE TABLE t4 (s1 int,primary key(s1));//

CREATE PROCEDURE p23 ()

BEGIN

DECLARE CONTINUE HANDLER

FOR SQLSTATE '23000' SET @x2 = 1;

SET @x = 1;

INSERT INTO t4 VALUES (1);

SET @x = 2;

INSERT INTO t4 VALUES (1); <--

SET @x = 3;

END;//

然后程序尝试再次往主键表中插入数值，但失败了，因为主键有唯一性限制。

7. DECLARE CONTINUE HANDLER example

CREATE TABLE t4 (s1 int,primary key(s1));//

CREATE PROCEDURE p23 ()

BEGIN

DECLARE CONTINUE HANDLER

FOR SQLSTATE '23000' SET @x2 = 1; <--

SET @x = 1;

INSERT INTO t4 VALUES (1);

SET @x = 2;

INSERT INTO t4 VALUES (1);

SET @x = 3;

END;//

由于插入失败，错误处理程序被触发，开始进行错误处理。下一个执行的语句是错误处理的语句，@x2被设为2。

8. DECLARE CONTINUE HANDLER example

CREATE TABLE t4 (s1 int,primary key(s1));//

CREATE PROCEDURE p23 ()

BEGIN

DECLARE CONTINUE HANDLER

FOR SQLSTATE '23000' SET @x2 = 1;

SET @x = 1;