Re: [Sqlalchemy-tickets] [sqlalchemy] #1401: support self-referential auto-joins when the foreign key joins to itself

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

#1401: support self-referential auto-joins when the foreign key joins to itself
---------------------------+---------------------------------------
      Reporter:  guest     |      Owner:  zzzeek
          Type:  defect    |     Status:  new
      Priority:  high      |  Milestone:  0.x.xx
     Component:  orm       |   Severity:  very major - up to 2 days
    Resolution:            |   Keywords:
Progress State:  in queue  |
---------------------------+---------------------------------------

Comment (by zzzeek):

 just to experiment with annotations in the primaryjoin:

 {{{
 #!diff
 diff -r 42694965987f lib/sqlalchemy/orm/properties.py
 --- a/lib/sqlalchemy/orm/properties.py  Wed Feb 01 10:14:28 2012 -0500
 +++ b/lib/sqlalchemy/orm/properties.py  Wed Feb 01 11:19:26 2012 -0500
 @@ -1052,6 +1052,9 @@
                      "'secondaryjoin' is needed as well."
                      % self)

 +        from sqlalchemy.sql import util as sql_util
 +        self.primaryjoin = sql_util._deep_annotate(self.primaryjoin,
 {'_nothing':True}, set())
 +
      def _columns_are_mapped(self, *cols):
          """Return True if all columns in the given collection are
          mapped by the tables referenced by this :class:`.Relationship`.
 }}}

 what fails here, at least one thing, is _create_lazy_clause() calculates
 improperly when it checks the "binds" collection.   We might want to make
 some small tests of annotated columns to see if they behave correctly in
 hash lookups (we seem to have this in test_selectable, though still seeing
 odd behavior here).

-- 
Ticket URL: <http://www.sqlalchemy.org/trac/ticket/1401#comment:11>
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