I have experienced the same sort of problem with trying to get rid of old portals.  Poking around in the database the problem seems to be

• deleting a portal removes all the entries from dbo.TabModules (and probably from all the dependent tables as well) so none of the tabs have any content
• the deletion process fails to remove entries from dbo.Tabs
• because there are entries in dbo.Tabs it is not possible to delete the entry for the portal in dbo.Portals

The work around seems to be to delete each entry in dbo.Tabs (I could only do this tab by tab in SQL Server Management Studio Express 2005).  Once there are no entries in dbo.Tabs the entry in dbo.Portals can be deleted.

It is possible that this will cause unforseen problems down the line so I do not recommend doing this.

From my perspective this seems to be a pretty basic bug, so I would be surprised if it will affect everyone.  It is possible that the problem is caused when the database has been upgraded many times, our current database has been in constant use since dnn v 3 and we are now up to 4.08.

Would it be possible/practical to add in the constraints to the live database?

If so is there a reference that will show all the constraints that should (now) exist in the core table structure.

I've just discovered I have this same problem in my 4.9.0 portal that has been upgraded since 4.3.x

Portals won't delete, giving the same error as the first post.

When I go into the tabs table and try and delete the tabs for the portal, one or more always refuses to be deleted. If I delete them one at a time, I can eventually delete them all. And then I can also finally delete the portal in Host, Portals.

Each time a tab won't delete, SQL Management Studio says "The DELETE statement conflicted with the SAME TABLE REFERENCE constraint "FK_Tabs_Tabs". The conflict occured in table "dbo.Tabs", column 'ParentId'. I don't know what to do with that. I've looked around but can't see anything obvious.

I've clicked through several of the items on the logs dropdown list in Host settings, but nothing seems to come up - the messages say it means it would have run correctly. I wouldnt' know what to look for anyway.

How can this be fixed?

Rob