Hi,
I am trying to map a relation in class which allows it to access
objects from a couple of tables away ie.
class Zone(object):
pass
class Sentence(object):
pass
class RawTag(object):
pass
class ProcessedTag(RawTag):
pass
mapper(RawTag, tag_table)
mapper(Sentence, sentence_table, "ptags":relation(RawTag,
primaryjoin=and_(sentences_table.c.sentence_id==tag_table.c.sentence_id,
tag_table_table.c.deleted==0 ), secondary=processed_tag_table) )
mapper(ProcessedTag, processed_tag_table)
mapper(Zone, zone_table)
There is a 1:M relation between Document and Sentence and between
Sentence and RawTag. I want to be able to access all of the
ProcessedTags for a Zone from the Zone class, I can do this for the
Sentences table using the "tags" relation that I defined. But I am
having trouble in allowing the same behaviour for Zone.
So I have tried to use primaryjoin in order to to do this but I am not
having any luck.
Among the many exceptions I can generate:
"ptags":relation(ProcessedTag,
primaryjoin=and_(and_(sentences_table.c.zone_id ==
zones_table.c.zone_id,
sentences_table.c.sentence_id==tags_table.c.sentence_id),
tags_table.c.deleted==0 ), secondary=processed_tag_table)
UnmappedColumnError: No column sentences.sentence_id is configured on
mapper Mapper|Zone|zones
Any pointers greatly appreciated!
Many thanks
Nathan
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