So, what would you suggest the "right answer" is in this case? In the
real world scenario we have a potentially good reason to avoid the
association proxy approach since that involves an additional table which
may be unneeded.
Is the best answer just to provide the foreign keys as I did?
On 4/19/2011 11:47 AM, Michael Bayer wrote:
On Apr 19, 2011, at 9:04 AM, Kent wrote:
I'm getting an SAWarning (0.6.4 and also 0.7b5dev) which has a message
that confuses me, so I've duplicated the problem with a script:
===================================================
mapper(PostSpotLight, spotlights_table,
properties = {'postkeywords':
relationship(Keyword, secondary=post_keywords,
primaryjoin=spotlights_table.c.post_id==post_keywords.c.post_id)}
)
[...]/sqlalchemy-default/lib/sqlalchemy/orm/properties.py:900:
SAWarning: No ForeignKey objects were present in secondary table
'post_keywords'. Assumed referenced foreign key columns
'post_keywords.keyword_id', 'post_keywords.post_id' for join condition
'spotlights.post_id = post_keywords.post_id' on relationship
PostSpotLight.postkeywords
eq_pairs = self._sync_pairs_from_join(self.primaryjoin, True)
Why is the complaint that there are No ForeignKey objects were present
in secondary table 'post_keywords', when clearly there are?
Well this is the message knowing something was wrong but not expressing it in a way that I expected when I
wrote it. post_keywords has no foreign keys that refer to the "spotlights" table. if a
primaryjoin condition is given, it only cares about foreign keys that express components of the join
condition. this used to be an error condition but eventually I figured that things would just
"work" if I assumed the cols in post_keywords were FKs, after I saw someone confused by placing a
"secondary" table that in fact had no FKs on it.
***Furthermore, if I pass the relationship this:
foreign_keys=[post_keywords.c.post_id,post_keywords.c.keyword_id]
then the warning goes away, but all I've done is specify the very
foreign_keys that already exist.***
well in this case you give it some columns, but not what they reference to. So it sees
"post_id" and it says, oh, thats the FK that points to spotlights.post_id.
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To post to this group, send email to [email protected].
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.
