腾讯游戏10大经典案例(二)：天堂等于天下

    天堂等于天下？是的，你的眼睛没有花~，看下面例子

mysql> create table t (a varchar(12) default null,b varchar(12) default null, unique key idx_a (a),unique key idx_b (b)) engine=innodb default charset=latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> 
mysql> insert into t values ("天堂",1);
Query OK, 1 row affected (0.00 sec)

mysql> 
mysql> insert into t values ("天下",1);
ERROR 1062 (23000): Duplicate entry ‘天下‘ for key ‘idx_a‘
mysql>

mysql> alter table t change a a varchar(20) CHARACTER SET latin1 collate latin1_bin;     
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> 
mysql> insert into t values ("天下",2); 
Query OK, 1 row affected (0.00 sec)

mysql> 

mysql> insert into t values (‘ABC‘,‘ABC‘); 
Query OK, 1 row affected (0.00 sec)

mysql> 
mysql> insert into t values (‘abc‘,‘ABC‘);   
ERROR 1062 (23000): Duplicate entry ‘abc‘ for key ‘idx_a‘
mysql>

  

腾讯游戏10大经典案例(二)：天堂等于天下

原文：http://blog.csdn.net/dba_waterbin/article/details/44678879