On Jul 20, 11:57 pm, Sean Davis <[EMAIL PROTECTED]> wrote:
> I have a table that has two columns that reference the same table in a
> foreign-key relationship. What do I need to specify and where to
> avoid the error below?
>
> <class 'sqlalchemy.exceptions.ArgumentError'>: Error determining
> primary and/or secondary join for relationship 'FeatureLoc.feature
> (Feature)'. If the underlying error cannot be corrected, you should
> specify the 'primaryjoin' (and 'secondaryjoin', if there is an
> association table present) keyword arguments to the relation()
> function (or for backrefs, by specifying the backref using the
> backref() function with keyword arguments) to explicitly specify the
> join conditions. Nested error is "Can't determine join between
> 'featureloc' and 'feature'; tables have more than one foreign key
> constraint relationship between them. Please specify the 'onclause' of
> this join explicitly."
>
> I am reflecting these tables from the database:
>
> feature_t = Table('feature',metadata,autoload=True)
> featureloc_t = Table('featureloc',metadata,autoload=True)
>
> class Feature(object):
> pass
>
> class FeatureLoc(object):
> pass
>
> sqlalchemy.orm.mapper(Feature,feature_t,properties={
> 'elements' : relation(Element,backref='feature')
> })
> sqlalchemy.orm.mapper(FeatureLoc,featureloc_t,properties={
> 'srcfeature' : relation(Feature),
> 'feature' : relation(Feature)
> })
Looks like this will do it:
sqlalchemy.orm.mapper(FeatureLoc,featureloc_t,properties={
'srcfeature' :
relation(Feature,primaryjoin=featureloc_t.c.srcfeature_id==feature_t.c.id,backref='features'),
'feature' :
relation(Feature,primaryjoin=featureloc_t.c.feature_id==feature_t.c.id)
})
Sorry for the noise.
Sean
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to sqlalchemy@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en
-~----------~----~----~----~------~----~------~--~---
