MySQL參數之lower_case_table_names

lower_case_table_names 參數MySQL 庫表 大小寫，默認為0
0 庫表敏感，區分大小寫，指定的大小寫保存文件
1 庫表不敏感，不區分大小寫，文件系統以小寫保存
2 使用Create語句指定的大小寫保存文件，但MySQL會將之轉化為小寫,啟動的時候日志報警告

參數從0調為1
lower_case_table_names =0下操作庫表都敏感

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

mysql> create  database 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)

調整參數lower_case_table_names =1
此時：兩表都有表信息，現在雖然有兩庫，但是在一庫中建立表，另一庫中也會出現表

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)

參數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(id  int);
Query OK, 0 rows affected (0.01 sec)

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

參數從0調到1，變化數據文件僅僅存放在小寫的庫中

[root@wxtest WX]# ls
db.opt
[root@wxtest wx]# ls
db.opt  t1.frm  t1.ibd  wx.frm  WX.frm  wx.ibd  WX.ibd