mysql error handler 例

错误控制

DECLARE { exit|continue } HANDLER FOR
{SQLSTATE [VALUE] | condition_name  | SQLWARNING  | NOT FOUND  | SQLEXCEPTION  | mysql_error_code}

SQLWARNING    是对所有以01开头的SQLSTATE代码的速记。
NOT FOUND     是对所有以02开头的SQLSTATE代码的速记。
SQLEXCEPTION  是对所有没有被SQLWARNING或NOT FOUND捕获的SQLSTATE代码的速记

example:
DECLARE EXIT HANDLER FOR 1452
begin
....
end;
切记, declare 后不需要 ;

前提

create table t1 ( id int not null auto_increment primary key ) engine=innodb;
create table t2 ( num int, key(num), foreign key(num) REFERENCES t1(id) ) engine=innodb;

错误日志记录
create table error_log (id int not null auto_increment primary key,
time datetime, code int,  msg varchar(80) );

create table t3 ( id int not null );

create table t4 ( id int check  id > 10 );

create table t5 ( id int not null auto_increment primary key, sex char(1), check sex in  ('m','f'));

ex1

ex: 希望记录 insert 失败的记录 (失败原因, 外键)

插入错误信息具有错误代码 ERROR 1452 (23000)


delimiter //
create procedure test12 ( in a int)
begin
DECLARE EXIT HANDLER FOR 1452
  begin
   insert into error_log (time,code, msg) values(now(), 1452, concat("t2 Foreign key reference failure for value=",a));
  end;
insert into t2 values (a);
end;
//
delimiter ;

ex2

更新 t1 表主键中涉及 t2 外键报错
ERROR 1451 (23000):

delimiter //
create procedure test18 ( in a int, in b int )
begin
DECLARE EXIT HANDLER FOR 1451
  begin
   insert into error_log (time,code, msg) values(now(), 1451, concat("t1 update faile, reference t2 for value=",b));
  end;
update t1 set id=b where id=a;
end;
//
delimiter ;

call test18(1,10);

ex3

t1 插入重复值 错误代码 1062

delimiter //
create procedure test13( in a int)
begin
declare exit  handler for 1062
begin
  insert into error_log (time,code, msg) values (now(), 1062, concat('t1 Duplicate entry=',a));
end;
insert into t1 values (a);
end;
//
delimiter ;

ex4

t3 表插入空值
假如直接插入, 则只出现警告, 默认使用 0 值取代

令无法插入 null 值

delimiter //
create procedure test15( in a int )
begin
declare exit handler for 1048
begin
  insert into error_log (time,code, msg) values (now(), 1048, 'table t3 empty values');
end;
insert into t3 values (a);
end;
//
delimiter ;

测试:
set @a=1;
call test15(@a); <- 插入t3;
call test15(@b); <- 插入error_log

ex5

参考官方 13.1.2. ALTER TABLE语法 描述:

所有的存储引擎均对CHECK子句进行分析，但是忽略CHECK子句  (参考 show create table t4, 没有check 语法)

只能够利用存储过程应用对应检查 令 check id > 10 生效

delimiter //
create procedure test16( in a int )
begin
  if a <= 10
  then
insert into error_log (time,code, msg) values (now(), 9901, concat('table t4 values less then 10, values=',a));
  else
    insert into t4 values (a);
  end if;
end;
//
delimiter ;

ex6

令 check sex in ('m','f') 生效

delimiter //
create procedure test17( in a char(1) )
begin
  if a <> 'm' and a <> 'f'
  then
insert into error_log (time,code, msg) values (now(), 9901, concat('table t5 sex values not in, values=',a));
  else
    insert into t5 (sex) values (a);
  end if;
end;
//
delimiter ;

ex7

t3 表插入空值  (使用 sqlstate 控制码)
假如直接插入, 则只出现警告, 默认使用 0 值取代,
令插入时具有默认值

tt@localhost[new]>insert into t3 values (@c);
ERROR 1048 (23000): Column 'id' cannot be null  [23000 <- 控制码]



delimiter //
create procedure test19( in a int )
begin
declare exit handler for SQLSTATE '23000'
begin
  insert into error_log (time,code, msg) values (now(), 23000, 'table t3 empty values');
  insert into t3 values (1);
end;
insert into t3 values (a);
end;
//
delimiter ;

测试:
set @a=1;
call test15(@a); <- 插入t3;
call test15(@b); <- 插入error_log 与 t3 表

ex8

错重错误定义 
create unique index id_idx on t3(id);

1. 重复键 [ERROR 1062 (23000)] 2. 插入字符, 第一次默认插入 0 3. 空值 [ERROR 1048 (23000):]
注意:  in a varchar(20) 才能够判断是否字符 int 则全自动转换成为数字

delimiter //
create procedure test21( in a varchar(20))
begin

declare exit handler for 1062
begin
  insert into error_log (time,code, msg) values (now(), 23000, 'table t3 duplicate key');
end;

declare exit handler for 1048
begin
   insert into error_log (time,code, msg) values (now(), 23000, 'table t3 null values');
end;

if ( a regexp  '^[[:digit:]]*$' ) = 1
then
  insert into t3 values (a);
else
  insert into error_log (time,code, msg) values (now(), 23000, 'table t3 not number');
end if;
end;
//
delimiter ;

 

判断纯字符函数

isnum() 函数

delimiter //
create function isnum( a char(20))
returns int
begin
declare r int;
select a regexp  '^[[:digit:]]*$' into r;
if r = 1
then
   return 1;
else
   return 0;
end if;
end;
//
delimiter ;