Re: [Sqlalchemy-tickets] [sqlalchemy] #2738: SQLAlchemy should throw an exception if there are multiple foreign keys to relate

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

#2738: SQLAlchemy should throw an exception if there are multiple foreign keys to
relate
----------------------------+----------------------------------
      Reporter:  Svenstaro  |      Owner:  zzzeek
          Type:  defect     |     Status:  new
      Priority:  high       |  Milestone:  0.8.xx
     Component:  schema     |   Severity:  minor - half an hour
    Resolution:             |   Keywords:
Progress State:  in queue   |
----------------------------+----------------------------------
Changes (by zzzeek):

 * priority:  medium => high
 * status_field:  awaiting triage => in queue
 * component:  cextensions => schema
 * severity:  no triage selected yet => minor - half an hour
 * milestone:   => 0.8.xx


Comment:

 yeah wow, weird how nobody finds these for so long.

 Here's that:

 {{{
 #!python
 from sqlalchemy import *

 m = MetaData()

 t1 = Table('t', m,
     Column('id', Integer, primary_key=True)
     )

 t2 = Table('t2', m,
     Column('id1', ForeignKey('t.id')),
     Column('id2', ForeignKey('t.id')),
 )

 s = select([t2]).alias()

 print t1.join(s)

 }}}

 here's the patch:

 {{{
 #!diff
 index 3a74cbd..1febb1b 100644
 --- a/lib/sqlalchemy/schema.py
 +++ b/lib/sqlalchemy/schema.py
 @@ -1134,7 +1134,9 @@ class Column(SchemaItem, expression.ColumnClause):
          information is not transferred.

          """
 -        fk = [ForeignKey(f.column) for f in self.foreign_keys]
 +
 +        fk = [ForeignKey(f.column, _constraint=f.constraint)
 +                    for f in self.foreign_keys]
          if name is None and self.name is None:
              raise exc.InvalidRequestError("Cannot initialize a sub-
 selectable"
                      " with this Column object until it's 'name' has "
 }}}

 need to also test `print id(fk.constraint.elements[0])`, etc.   should go
 into test_selectable.

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2738#comment:1>
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