Bug #14506 | `INFORMATION_SCHEMA`.`COLUMNS`.`COLUMN_COMMENT` is allways emtpy | ||
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Submitted: | 31 Oct 2005 10:05 | Modified: | 31 Oct 2005 11:22 |
Reporter: | MySQL-Front Team | Email Updates: | |
Status: | Can't repeat | Impact on me: | |
Category: | MySQL Server | Severity: | S3 (Non-critical) |
Version: | 5.0.15 | OS: | Windows (Windows XP) |
Assigned to: | CPU Architecture: | Any |
[31 Oct 2005 10:05]
MySQL-Front Team
[31 Oct 2005 11:22]
Valeriy Kravchuk
Thank you for a feature request. For me it looks like column comment propagates to view (both on 5.0.15-nt on Windows and on 5.0.16-BK on Linux): mysql> create table tc (c1 int comment 'useful column'); Query OK, 0 rows affected (0,01 sec) mysql> select column_name, column_comment from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'tc'; +-------------+----------------+ | column_name | column_comment | +-------------+----------------+ | c1 | useful column | +-------------+----------------+ 1 row in set (0,01 sec) mysql> create view vc as select * from tc; Query OK, 0 rows affected (0,00 sec) mysql> select column_name, column_comment from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'vc'; +-------------+----------------+ | column_name | column_comment | +-------------+----------------+ | c1 | useful column | +-------------+----------------+ 1 row in set (0,01 sec) mysql> show create table tc; +-------+----------------------------------------------------------------------- -----------------------------------------+ | Table | Create Table | +-------+----------------------------------------------------------------------- -----------------------------------------+ | tc | CREATE TABLE `tc` ( `c1` int(11) default NULL COMMENT 'useful column' ) ENGINE=MyISAM DEFAULT CHARSET=latin1 | +-------+----------------------------------------------------------------------- -----------------------------------------+ 1 row in set (0,00 sec) mysql> show create view vc; +------+------------------------------------------------------------------------ ----------------------------------------------------+ | View | Create View | +------+------------------------------------------------------------------------ ----------------------------------------------------+ | vc | CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `vc` AS select `tc`.`c1` AS `c1` from `tc` | +------+------------------------------------------------------------------------ ----------------------------------------------------+ 1 row in set (0,00 sec) mysql> select table_name, column_name, column_comment from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'vc'; +------------+-------------+----------------+ | table_name | column_name | column_comment | +------------+-------------+----------------+ | vc | c1 | useful column | +------------+-------------+----------------+ 1 row in set (0,01 sec) mysql> select version(); +-----------+ | version() | +-----------+ | 5.0.16 | +-----------+ 1 row in set (0,01 sec) Explicit column comment for views are unsupported (http://dev.mysql.com/doc/refman/5.0/en/create-view.html): mysql> create view vc2 (c2 comment 'I am in view') as select * from tc; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'comment 'I am in view') as select * from tc' at line 1 You may add a separate feature request for that. But exisiting comments are used, even if view columns have different names: mysql> create view vc2 (c2) as select * from tc; Query OK, 0 rows affected (0,00 sec) mysql> select table_name, column_name, column_comment from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = 'vc2'; +------------+-------------+----------------+ | table_name | column_name | column_comment | +------------+-------------+----------------+ | vc2 | c2 | useful column | +------------+-------------+----------------+ 1 row in set (0,02 sec)
[31 Oct 2005 12:07]
MySQL-Front Team
I'm sorry, you are right: There is no bug! Thanks a lot for your comments about view column comments!