daniil-berg
commented
1 year ago I can confirm. Here is a simplified version for testing (compatible with Python 3.7+):
from typing import List, Optional
from sqlmodel import Field, SQLModel, create_engine, Session, Relationship
class Foo(SQLModel, table=True):
id: Optional[int] = Field(primary_key=True)
bars: List["Bar"] = Relationship(back_populates="foo")
class Bar(SQLModel, table=True):
__mapper_args__ = {
"polymorphic_on": "type",
"polymorphic_identity": "x",
}
id: Optional[int] = Field(primary_key=True)
type: str = Field(default="x")
foo_id: Optional[int] = Field(foreign_key="foo.id")
foo: Optional[Foo] = Relationship(back_populates="bars")
class BarY(Bar, table=True):
__mapper_args__ = {
"polymorphic_identity": "y",
}
class BarZ(Bar, table=True):
__mapper_args__ = {
"polymorphic_identity": "z",
}
db_url = f"sqlite:///:memory:"
engine = create_engine(db_url, echo=True)
SQLModel.metadata.create_all(engine)
with Session(engine) as session:
foo = Foo()
foo.bars.extend([BarY(), Bar()])
session.add(foo)
session.commit()The full error: (Click to expand)
``` Traceback (most recent call last): File "/home/daniil/coding/sqlmodel/polymorphic.py", line 45, inHere is an analogous version in pure SQLAlchemy working with no errors: (Click to expand)
```python from sqlalchemy.engine.create import create_engine from sqlalchemy.orm import relationship from sqlalchemy.orm.decl_api import declarative_base from sqlalchemy.sql.schema import Column, ForeignKey from sqlalchemy.orm.session import Session from sqlalchemy.sql.sqltypes import Integer, String Base = declarative_base() class Foo(Base): __tablename__ = 'foo' id = Column(Integer, primary_key=True) bars = relationship("Bar", back_populates="foo") class Bar(Base): __tablename__ = 'bar' __mapper_args__ = { "polymorphic_on": "type", "polymorphic_identity": "x", } id = Column(Integer, primary_key=True) type = Column(String, default="x") foo_id = Column(ForeignKey("foo.id")) foo = relationship("Foo", back_populates="bars") class BarY(Bar): __mapper_args__ = { "polymorphic_identity": "y", } class BarZ(Bar): __mapper_args__ = { "polymorphic_identity": "z", } db_url = f"sqlite:///:memory:" engine = create_engine(db_url, echo=True) Base.metadata.create_all(engine) with Session(engine) as session: foo = Foo() foo.bars.extend([BarY(), Bar()]) session.add(foo) session.commit() ```Interestingly, you get a different error, if you instead just try to instantiate a BarY object:
...
with Session(engine) as session:
bar = BarY()
session.add(bar)
session.commit()The full error: (Click to expand)
``` Traceback (most recent call last): File "/home/daniil/coding/sqlmodel/polymorphic.py", line 46, inI tried debugging the SQLModelMetaclass.__new__ method, to see if the __mapper_args__ end up on the resulting class, and it seems like they are. I checked this line here:
new_cls = super().__new__(cls, name, bases, dict_used, **config_kwargs)When setting up Bar for example, the new_cls.__dict__ contains the key value pair:
__mapper_args__: {'polymorphic_on': 'type', 'polymorphic_identity': 'x'}So that seems not to be the issue.
This is all I got so far.
zopyx
mxdev88
KunxiSun
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Example Code
Description
I have this PoC-style code that would model a 1:n relationship between one
InvoiceRequestand multipleInvoices.There are several invoice types
ÃŒnvoiceReversalandInvoiceCorrectionthat are modelled using the inheritance fromInvoiceclass and polymorphic identity.However. the derived classes are obviously not mapped:
sqlalchemy.orm.exc.UnmappedClassError: Class '__main__.InvoiceReversal' is not mappedI could not find a solution how to resolve this.
Operating System
Linux
Operating System Details
Linux
SQLModel Version
SQLAlchemy==1.4.40
Python Version
3.10
Additional Context