Question

I have errors when i try to query my MySQL tables in lowercase :

mysql> select * from selection_vc limit 1;
ERROR 1146 (42S02): Table 'mydb.selection_vc' doesn't exist

When I use uppercase, everything is OK :

mysql> select * from SELECTION_VC limit 1;
+-------------+-------------+-------------+--------+
| CAMPAIGN_ID | CONTACT_ID  | COLUMN_NAME | MONTH  |
+-------------+-------------+-------------+--------+
| ALCA-32515W | ALCA-2X08DX | A           | 201207 |
+-------------+-------------+-------------+--------+
1 row in set (0.00 sec)

I have this error(feature?) only on table names, column names can be accessed either in lowercase or uppercase. This occurs only in the database I have installed on Linux, the one on my Mac does not have this issue.

Did i miss something in MySQL configuration or is this a bug ?

Answer 1

As described in the Identifier Case Sensitivity section of the manual:

In MySQL, databases correspond to directories within the data directory. Each table within a database corresponds to at least one file within the database directory (and possibly more, depending on the storage engine). Triggers also correspond to files. Consequently, the case sensitivity of the underlying operating system plays a part in the case sensitivity of database, table, and trigger names. This means such names are not case sensitive in Windows, but are case sensitive in most varieties of Unix. One notable exception is Mac OS X, which is Unix-based but uses a default file system type (HFS+) that is not case sensitive.

It goes on to say:

To avoid data transfer problems arising from lettercase of database or table names, you have two options:

• Use lower_case_table_names=1 on all systems. The main disadvantage with this is that when you use SHOW TABLES or SHOW DATABASES, you do not see the names in their original lettercase.

• Use lower_case_table_names=0 on Unix and lower_case_table_names=2 on Windows. This preserves the lettercase of database and table names. The disadvantage of this is that you must ensure that your statements always refer to your database and table names with the correct lettercase on Windows. If you transfer your statements to Unix, where lettercase is significant, they do not work if the lettercase is incorrect.

  Exception: If you are using InnoDB tables and you are trying to avoid these data transfer problems, you should set lower_case_table_names to 1 on all platforms to force names to be converted to lowercase.