On Tue, Aug 12, 2008 at 06:18:39PM +0200, Luis Javier Peris wrote:
> I'd like to know if there is a restriction using inheritance about
> multiplejoin function because I'm getting an error and I don't know why.
> I've the following code:
>
> class Question(InheritableSQLObject):
>     filename = StringCol(default=None, length=255, unique=True)
>     title = StringCol(default=None)
>     default_mark = FloatCol(default=0.0)
>     wording = RelatedJoin('Content')
>     term_questions = RelatedJoin('Term', joinColumn='term',
> otherColumn='question',
>                                  intermediateTable='Term_questions')
>     answers = MultipleJoin('Answer')
>     questionref = MultipleJoin('QuestionRef')
>
>
> class Answer(SQLObject):
>     value = StringCol(default=None)
>     calification = FloatCol(default=None)
>     ide = StringCol(default=None)
>     question = ForeignKey('Question')
>
>
> class Ord(Question):
>     _inheritable = False
>     shuffle = BoolCol()
>     orderanswers = MultipleJoin('OrderChoice')
>
>
> class OrderChoice(SQLObject):
>     value = StringCol(default=None)
>     ord = IntCol(default=None)
>     ide = StringCol(default=None)
>     question = ForeignKey('Ord')
>
> and when I've a Ord instance (called 'q') and I do 'q.orderanswers' I get
> the following error:
>
> sqlobject.dberrors.OperationalError: Unknown column 'ord_id' in 'where
> clause'

  It has nothing with inheritance. I simplified the program (you have to
do this yourself) to:

class Ord(SQLObject):
   orderanswers = MultipleJoin('OrderChoice')

class OrderChoice(SQLObject):
   question = ForeignKey('Ord')

Ord.createTable()
OrderChoice.createTable()

ord = Ord()
print ord.orderanswers

  and got the same error. Well, with this simple program and SQL it
generates it easy to see where is the problem:

 1/QueryR  :  CREATE TABLE ord (
   id INTEGER PRIMARY KEY
)
 2/QueryR  :  CREATE TABLE order_choice (
   id INTEGER PRIMARY KEY,
   question_id INT CONSTRAINT question_id_exists REFERENCES ord(id)
)
 3/QueryR  :  INSERT INTO ord VALUES (NULL)
 4/QueryR  :  SELECT NULL FROM ord WHERE ((ord.id) = (1))
 5/QueryR  :  SELECT id FROM order_choice WHERE ord_id = (1)

Oleg.
--
    Oleg Broytmann            http://phd.pp.ru/            phd <at> phd.pp.ru
          Programmers don't die, they just GOSUB without RETURN.

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