Bug #59856 Clearing a DATETIME column's default value has no effect
Submitted: 31 Jan 2011 23:27 Modified: 1 Feb 2011 20:45
Reporter: Yvan Rodrigues Email Updates:
Status: Can't repeat Impact on me:
Category:MySQL Workbench: SQL Editor Severity:S3 (Non-critical)
Version:5.2.31 OS:Windows
Assigned to: CPU Architecture:Any

[31 Jan 2011 23:27] Yvan Rodrigues
The application does not acknowledge that changing a column's default value puts the table in a dirty state.

How to repeat:
- Right click a table | Alter table...
- Switch to Columns tab
- Change the default value for an existing column
- Click Apply

Message returned: No changes to object were detected.

If you make other changes that work, such as adding a column, only that change is acknowledged, not the change to default value.

Suggested fix:
Change in default value should put the object into a dirty state.
[1 Feb 2011 4:19] Valeriy Kravchuk
What version of server are you working with? 

On Mac OS X I see ALTER generated in such cases:

ALTER TABLE `test`.`t73` CHANGE COLUMN `col805` `col805` VARCHAR(51) CHARACTER SET 'utf8' NULL DEFAULT 'ddddd'  ;

Will check on Windows later.
[1 Feb 2011 15:59] Yvan Rodrigues
Can only reproduce by clearing default value of a DATETIME column
[1 Feb 2011 17:56] Valeriy Kravchuk
Still can not repeat on Mac OS X. After clearing default value ('2011-02-01 19:54:16') of the DATETIME column the following code was generated:

ALTER TABLE `test`.`t73` CHANGE COLUMN `col790` `col790` DATETIME NULL  ;
[1 Feb 2011 20:46] MySQL Verification Team
I couldn't repeat on Windows Vista too.