-- Update table [CMS_WebPartLayout]
DROP INDEX [IX_CMS_WebPartLayout_WebPartLayoutCheckedOutByUserID]
    ON [CMS_WebPartLayout];

ALTER TABLE [CMS_WebPartLayout]
    DROP CONSTRAINT [FK_CMS_WebPartLayout_WebPartLayoutCheckedOutByUserID_CMS_User];

ALTER TABLE [CMS_WebPartLayout]
    DROP
        COLUMN [WebPartLayoutCheckedOutByUserID],

        COLUMN [WebPartLayoutCheckedOutFilename],

        COLUMN [WebPartLayoutCheckedOutMachineName];

ALTER TABLE [CMS_WebPartLayout]
    ADD
        CONSTRAINT [DEFAULT_CMS_WebPartLayout_WebPartLayoutCodeName]
            DEFAULT ('') FOR [WebPartLayoutCodeName],
        CONSTRAINT [DEFAULT_CMS_WebPartLayout_WebPartLayoutDisplayName]
            DEFAULT ('') FOR [WebPartLayoutDisplayName];

Failed to run SQLscript: 'FK_CMS_WebPartLayout_WebPartLayoutCheckedOutByUserID_CMS_User' is not a constraint.
Could not drop constraint. See previous errors.