I have a certain ORM model that is being referenced from several other models. 
I don't want the user to be able to delete rows from that table that are still 
being referenced elsewhere.

Ideally I would like something like:
    refs = get_references(row)
    if refs:
        print "Can't delete row because of:"
        for ref in refs:
            print ref
    else:
        self.session.delete(row)

Or even just:
    if is_being_referenced(row):
        print "You can't delete that!"
    else:
        self.session.delete(row)

If there's no way to do either of those, then I would settle for:
    try:
        self.session.delete(row)
    except sql.exc.DeletionError:
        print "You can't delete that!"
        #Again, a way to get a list of the offending references would be nice!

I tried doing the above, catching IntegrityError, but the problem is that SQLA 
doesn't 'notice' the error and tell me about it until another action occurs 
that causes other queries to be run. Is there some way I can make SQLA check 
the integrity of the database immediately after the deletion? Preferably 
without running unnecessary queries if that's going to cause a performance hit.

Cheers,
Cam
Cameron Jackson
Engineering Intern
Air Operations
Thales Australia
Thales Australia Centre, WTC Northbank Wharf, Concourse Level,
Siddeley Street, Melbourne, VIC 3005, Australia
Tel: +61 3 8630 4591
cameron.jack...@thalesgroup.com.au<mailto:cameron.jack...@thalesgroup.com.au> | 
www.thalesgroup.com.au<http://www.thalesgroup.com.au>


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