Hey Michael,
Great, rev 1555 worked for me! If it would help, please convert this lot
into a unit test/s. I'll keep on going and will let you know if any more
issues arise.
Thanks!
Nick
Michael Bayer wrote:
> hey Nick -
>
> these are terrific tests, sorry i didnt have this all working ahead of
> time but this is how this stuff has ended up getting done in a lot of
> cases...
>
> made a few tweaks to polymorphic loading in changeset 1555. a few
> changes to your script, which is attached. the "default='0'" on all
> your ID columns was confusing it in many cases, so i took those out
> (if you really need those there, we can look into making them less
> confusing to the mapper). secondly, since you are making a
> relationship directly to the MagazinePage mapper which you want to be
> polymorphic towards the ClassifiedPage mapper, that mapper needs its
> own polymorphic selectable (and i am blown away that this works at
> all...i hadnt taken it this far):
>
> page_join = polymorphic_union(
> {
> 'm': page_table.join(magazine_page_table),
> 'c':
> page_table.join(magazine_page_table).join(classified_page_table),
> 'p': page_table.select(page_table.c.type=='p'),
> }, None, 'page_join')
>
> magazine_join = polymorphic_union(
> {
> 'm': page_table.join(magazine_page_table),
> 'c':
> page_table.join(magazine_page_table).join(classified_page_table),
> }, None, 'page_join')
>
> page_mapper = mapper(Page, page_table, select_table=page_join,
> polymorphic_on=page_join.c.type, polymorphic_identity='p')
>
> magazine_page_mapper = mapper(MagazinePage, magazine_page_table,
> select_table=magazine_join, inherits=page_mapper,
> polymorphic_identity='m', properties={
> 'magazine': relation(Magazine, backref=backref('pages'))
> })
>
> classified_page_mapper = mapper(ClassifiedPage, classified_page_table,
> inherits=magazine_page_mapper, polymorphic_identity='c')
>
> so the attached file does that and also retrieves two ClassifiedPage
> and one MagazinePage off the relationship.
>
> Would there be any issue if I converted these scripts into further
> unit tests to be included with the SA distribution ? youve come
> across some patterns that have not been done before and these are very
> useful.
>
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