Okay - I gotcha!
That makes perfect sense too. It also means that my (eventual) work around
worked:
class Round(Base):
__table__ = round_join
game_id = column_property(
round_table.c.game_id, game_table.c.id,
game_language_table.c.game_id)
On Wed, Aug 21, 2019 at 2:21 PM Mike Bayer <mike...@zzzcomputing.com> wrote:
>
>
> On Wed, Aug 21, 2019, at 1:46 PM, Michael P. McDonnell wrote:
>
> Hey team -
>
> I've went through the docs, and likely because I'm a bit of a hack - I'm
> finding it hard to find my answers (because I'm not sure what I'm
> specifically looking to "do" other than "make it work")
>
> So I have the following situation:
> I have a GAME table (with a corresponding LANGUAGE table) - because my
> users might play games.
>
>
>
>
>
>
>
>
>
>
>
>
> *game_language_table = Table( 'game_language', Base.metadata,
> Column('game_id', UUID(as_uuid=True), ForeignKey('game.id
> <http://game.id>'), primary_key=True, nullable=False),
> Column('language_id', String(length=255), ForeignKey('language.id
> <http://language.id>'), primary_key=True, nullable=False),
> Column('name', String(length=255), nullable=False, unique=True))game_table
> = Table( 'game', Base.metadata, Column('id', UUID(as_uuid=True),
> primary_key=True, nullable=False,
> default=sqlalchemy.text('uuid_generate_v4()'),
> server_default=sqlalchemy.text('uuid_generate_v4()')),
> Column('join_code', String(length=8), nullable=False, unique=True))*
> I also have a ROUND table which is effectively just an extension of a
> game, but with a sequence number. Basically - if I have a collection of
> games that I want users to play - they play them as "Rounds" in a given
> order.
>
>
>
>
>
>
>
>
> *round_table = Table( 'round', Base.metadata, Column('id',
> UUID(as_uuid=True), primary_key=True, nullable=False,
> default=sqlalchemy.text('uuid_generate_v4()'),
> server_default=sqlalchemy.text('uuid_generate_v4()')),
> Column('tournament_id', UUID(as_uuid=True), ForeignKey('tournament.id
> <http://tournament.id>'), nullable=False), Column('game_id',
> UUID(as_uuid=True), ForeignKey('game.id <http://game.id>'),
> nullable=False), Column('sequence', Integer, nullable=False,
> default=0), UniqueConstraint('tournament_id', 'sequence'))*
> So my GAME table has an "id" field, and my round table has a game_id
> field, and an id field.
>
> When I try to join(game_table, round_table) - I get the following error:
> *Implicitly combining column round.id <http://round.id> with column
> game.id <http://game.id> under attribute 'id'. Please configure one or
> more attributes for these same-named columns explicitly.*
>
>
> join() does not emit that error; that error occurs when you create a
> mapping to the join using either mapper() or a declarative base, since
> "attribute" refers to ORM mapped attribute. Mapping to joins with
> same-named columns is demonstrated at
> https://docs.sqlalchemy.org/en/13/orm/nonstandard_mappings.html#mapping-a-class-against-multiple-tables
> .
>
>
>
>
>
> So - because there's multiple points of entry into these tables: Editing a
> Game is a direct thing, editing a round (which also edits its underlying
> game) is also a direct thing.
>
> How do I craft the JOIN so I don't step on toes?
>
> I tried doing the following:
> *round_join = join(round_table, game_join.alias('game'))*
> That didn't help, because game_id still squashes between game_language and
> round.
>
> Is there a smarter way to go about this?
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
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>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
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> .
>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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