Re: [Sqlalchemy-tickets] [sqlalchemy] #2501: the DELETE before INSERT problem

[sqlalchemy <mi...@zz...>]

#2501: the DELETE before INSERT problem
------------------------------+---------------------------------------
      Reporter:  zzzeek       |      Owner:  zzzeek
          Type:  defect       |     Status:  new
      Priority:  high         |  Milestone:  0.9.xx
     Component:  orm          |   Severity:  very major - up to 2 days
    Resolution:               |   Keywords:
Progress State:  needs tests  |
------------------------------+---------------------------------------

Comment (by schlamar):

 Looks like resetting all order_by properties of revived objects does the
 trick:


 {{{
 #!python

 def get_order_by_properties(model, relation_name):
     relation = getattr(model, relation_name)
     if (hasattr(relation, 'property') and
             isinstance(relation.property, RelationshipProperty)):
         if relation.property.order_by:
             return [c.name for c in relation.property.order_by]
     return list()


 value = [get_related_obj(session, obj, v, field) for v in value]
 setattr(obj, field, list())
 session.flush()  # possibly trigger delete cascade
 for v in value:
     state = inspection.inspect(v)
     if state.deleted:
         orm.make_transient(v)  # put it back to life

         # reset order by fields
         for attr in get_order_by_properties(type(obj), field):
             if hasattr(v, attr):
                 setattr(v, attr, None)
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2501#comment:14>
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