I would need to see what get_mapper() is doing. the best way to associate the
relevant table to a mapper is to look at inspect(Class).mapper.local_table.
On Wed, May 26, 2021, at 9:18 AM, Piotr wrote:
> I'm updating "sqlalchemy_django_query" for SQLAlchemy 1.4 and aside of that I
> found a peculiar problem - when I call get_mapper on a table
> (AnnotatedTable) I get a ValueError due to multiple mappers found.
>
> The model is inherited by two other models and get_mapper finds mappers for
> all 3 models due to this:
>
>
> class Conversation(db.Base):
> __tablename__ = 'conversation'
> id = sqlalchemy.Column(postgres_dialect.UUID(as_uuid=True),
> primary_key=True, default=uuid.uuid4)
> ...
> type = sqlalchemy.Column(sqlalchemy.Text, nullable=False)
>
> __mapper_args__ = {
> 'polymorphic_identity': 'conversation',
> 'polymorphic_on': type,
> }
>
>
> ...
>
>
> class ContactFormConversation(Conversation):
> __tablename__ = 'contact_form_conversation'
> id = sqlalchemy.Column(sqlalchemy.ForeignKey('conversation.id'),
> primary_key=True, nullable=False)
> ...
>
> __mapper_args__ = {
> 'polymorphic_identity': 'contact_form_conversation',
> }
>
>
> ...
>
>
> class RatingConversation(Conversation):
> __tablename__ = 'rating_conversation'
> id = sqlalchemy.Column(sqlalchemy.ForeignKey('conversation.id'),
> primary_key=True, nullable=False)
> ...
>
> __mapper_args__ = {
> 'polymorphic_identity': 'rating_conversation',
> }
>
>
> Should the model structure be done differently?
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
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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
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