"ValueError: <class 'src.models.calls.Call'> has no matching SQLAlchemy type" when adding Relationship

[GigaDroid]

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Example Code

from sqlmodel import Field, Relationship, SQLModel
from datetime import datetime
from uuid import UUID, uuid4

class Call(SQLModel, table=True):
    id: UUID | None = Field(default_factory=uuid4, primary_key=True)
    messages: list["Transcription"] = Relationship(back_populates="call")


### TRANSCRIPT ###

class BaseTranscription(SQLModel):
    id: UUID | None = Field(default_factory=uuid4, primary_key=True)
    message: str
    timestamp: datetime
    is_remote: bool
    is_final: bool
    call_id: UUID = Field(foreign_key="call.id")
    call: Call = Relationship(back_populates="messages")

class Transcription(BaseTranscription, table=True):
    pass

Description

Hey, I have the following classes as shown in the example code. If I run this I get the following error:
ValueError: <class 'src.models.calls.Call'> has no matching SQLAlchemy type

However, when I run this after removing "call: Call = Relationship(back_populates="messages")" from the BaseTranscription class it actually works. I'm folllowing the documentation (https://sqlmodel.tiangolo.com/tutorial/relationship-attributes/back-populates/#fix-it-using-back_populates) and it should be the same so I don't see why this doesn't work.

Operating System

macOS

Operating System Details

No response

SQLModel Version

0.0.16

Python Version

3.12.2

Additional Context

No response

[joachimhuet]

class BaseTranscription(SQLModel): is not a table add table=True for it to be recognized as a table, if the table is actually the Transcription class move there the relationship:

class BaseTranscription(SQLModel):
    call: Call # optional if you don't need it on your base class

class BaseTranscription(BaseTranscription, table=True):
    call: Call = Relationship(back_populates="messages") # relationships should be defined on tables only

[GigaDroid]

@joachimhuet I'm sorry I forgot the last part of the example code. Here it is:
class Transcription(BaseTranscription, table=True): pass

[joachimhuet]

Well then, as I stated in my answer you can move the relationship in the Transcription class and it will work. You can still keep call: Callin the base class but just without the = Relationship(...) part. 😸