micromax 发表于 2018-10-7 06:10:13

MySQL参数之lower_case_table_names

  lower_case_table_names 参数MySQL 库表 大小写,默认为0
  0 库表敏感,区分大小写,指定的大小写保存文件
  1库表不敏感,不区分大小写,文件系统以小写保存
  2使用Create语句指定的大小写保存文件,但MySQL会将之转化为小写,启动的时候日志报警告

  参数从0调为1
  lower_case_table_names =0下操作库表都敏感
  

  
mysql> createdatabase wx;
  
Query OK, 1 row affected (0.01 sec)
  

  
mysql> createdatabase WX;
  
Query OK, 1 row affected (0.00 sec)
  

  
mysql> use wx;
  
Database changed
  
mysql> show tables;
  
Empty set (0.00 sec)
  

  
mysql> create table wx(id int);
  
Query OK, 0 rows affected (0.01 sec)
  

  
mysql> create table WX(id int);
  
Query OK, 0 rows affected (0.01 sec)
  

  

  调整参数lower_case_table_names =1
  此时:两表都有表信息,现在虽然有两库,但是在一库中建立表,另一库中也会出现表
  

mysql> use wx;  
Reading table information for completion of table and column names
  
You can turn off this feature to get a quicker startup with -A
  

  
Database changed
  
mysql> show tables;
  
+--------------+
  
| Tables_in_wx |
  
+--------------+
  
| WX         |
  
| wx         |
  
+--------------+
  
2 rows in set (0.00 sec)
  

  
mysql> use WX;
  
Reading table information for completion of table and column names
  
You can turn off this feature to get a quicker startup with -A
  

  
Database changed
  
mysql> show tables;
  
+--------------+
  
| Tables_in_wx |
  
+--------------+
  
| WX         |
  
| wx         |
  
+--------------+
  
2 rows in set (0.00 sec)
  

  参数lower_case_table_names =1下操作
  

mysql> create database ww;  
Query OK, 1 row affected (0.01 sec)
  

  
mysql> create database WW;
  
ERROR 1007 (HY000): Can't create database 'ww'; database exists
  
mysql> use ww;
  
Database changed
  
mysql> create table ww(idint);
  
Query OK, 0 rows affected (0.01 sec)
  

  
mysql> create table WW(idint);
  
ERROR 1050 (42S01): Table 'ww' already exists
  

  

  参数从0调到1,变化数据文件仅仅存放在小写的库中
  

# ls  
db.opt
  
# ls
  
db.optt1.frmt1.ibdwx.frmWX.frmwx.ibdWX.ibd


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