UnmappedColumnError when using mapped_args and version_id_col for optimistic concurrency control

[jruizaranguren]

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Example Code

import sqlalchemy as sa
from sqlmodel import Field, SQLModel, create_engine, Session

class Record(SQLModel, table=True):
    """Status list for credentials."""

    __tablename__ = "records"

    id: int | None = Field(default=None, primary_key=True, unique=True)
    name: str
    version: int = Field(sa_column=sa.Column(sa.Integer, nullable=False, default=1))
    
    __mapper_args__ = {
        "version_id_col": sa.Column("version", sa.Integer, nullable=False, default=1),
        "version_id_generator": False}
    
engine = create_engine("sqlite:////tmp/test.db")

record = Record(name="test")

SQLModel.metadata.create_all(engine, tables=[Record.__table__])

with Session(engine) as session:
    session.add(record)
    session.commit()
    session.refresh(record)

Description

• Create a model with a version_id_col so sqlalchemy can handle optimistic concurrency for me
• I expect the record is created
• Then I would expect that version will be checked in every update, but I'm stuck in the first step.

But I'm getting the following exception:
sqlalchemy.orm.exc.UnmappedColumnError: No column version is configured on mapper Mapper[Record(records)]...

Operating System

Linux

Operating System Details

Ubuntu 20.04

SQLModel Version

0.0.22

Python Version

3.10.12

Additional Context

SQLAlchemy documentation of version_id_col in mapper_args.

[jruizaranguren]

For those having similar problems, I found the solution, which is using the sa_column attribute of the model field:

class Record(SQLModel, table=True):
    """Status list for credentials."""

    __tablename__ = "records"

    id: int | None = Field(default=None, primary_key=True, unique=True)
    name: str
    version: int = Field(sa_column=sa.Column(sa.Integer, nullable=False, default=1))
    
    __mapper_args__ = {
        "version_id_col": version.sa_column,
        "version_id_generator": False}