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On 2014-08-20 6:42 PM, Murali Balcha wrote:
>
> I can successfully add string column parent_id without any problem.
> However adding a boolean column is vexing. Adding a boolean column adds
> a check constraint on the table but when I remove the column in the
> downgrade, the check constraint for snapshot still remains on the table
> which resulting in the following exception. Has anyone run into this
> problem?
>
> OperationalError: (OperationalError) no such column: snapshot u'\nCREATE
> TABLE backups (\n\tcreated_at DATETIME, \n\tupdated_at DATETIME,
> \n\tdeleted_at DATETIME, \n\tdeleted BOOLEAN, \n\tid VARCHAR(36) NOT
> NULL, \n\tvolume_id VARCHAR(36) NOT NULL, \n\tuser_id VARCHAR(255),
> \n\tproject_id VARCHAR(255), \n\thost VARCHAR(255),
> \n\tavailability_zone VARCHAR(255), \n\tdisplay_name VARCHAR(255),
> \n\tdisplay_description VARCHAR(255), \n\tcontainer VARCHAR(255),
> \n\tstatus VARCHAR(255), \n\tfail_reason VARCHAR(255),
> \n\tservice_metadata VARCHAR(255), \n\tservice VARCHAR(255), \n\tsize
> INTEGER, \n\tobject_count INTEGER, \n\tparent_id VARCHAR(255),
> \n\tPRIMARY KEY (id), \n\tCHECK (deleted IN (0, 1)), \n\tCHECK (snapshot
> IN (0, 1))\n)\n\n' ()
>

I had a similar issue when trying to add a boolean column to 
volume_types in Cinder. It looks sqlite does not support DROP CHECK 
required by the downgrade process, therefore resulting in the error you see.

You have to create a sql script specifically for sqlite.

See my change: https://review.openstack.org/#/c/114395/6

In cinder/db/sqlalchemy/migrate_repo/versions/024_sqlite_downgrade.sql
	
The "hack" consists of creating a new table without the column and 
copying over the data to it.

-- 
Mathieu