CODEWITHSUNDEEP
pythonsqlalchemyfastapimypy
carloe
carloe

Reputation: 1540

Updating a boolean property in SQLAlchemy(2.x) model while satisfying MyPy

I am trying to update a boolean property in my SQLAlchemy model and I want to make sure MyPy is satisfied with the code as well. However, MyPy is giving me an error when I try to update the property. Here's the error message:

dashing/db/dao/workspace_dao.py:69: error: Incompatible types in assignment
(expression has type "bool", variable has type "Column[bool]")  [assignment]
            workspace.is_archived = new_value
                                    ^~~~~~~~~
Found 1 error in 1 file (checked 57 source files)

This is the function I am using to update the property:

    async def archive_workspace(
        self,
        workspace_id: UUID,
        new_value: bool,
    ) -> Optional[WorkspaceModel]:
        workspace = await self.session.get(WorkspaceModel, workspace_id)
        if workspace is None:
            return None
        workspace.is_archived = new_value  # ← MyPy does not like this assignment
        await self.session.commit()
        return workspace

And here is my model definition:

class WorkspaceModel(Base):
    __tablename__ = "workspace"

    ...

    is_archived = Column(Boolean, unique=False, default=False)

What is the correct way to update the boolean property in my SQLAlchemy model so that MyPy does not raise any errors?

Upvotes: 1

Views: 2042

Answers (1)

carloe
carloe

Reputation: 1540

As @python_user mentioned in his comment, I was using old syntax. Using SQLAlchemy 2.0 syntax fixes the issue:

from sqlalchemy.orm import Mapped, mapped_column

class WorkspaceModel(Base):
    __tablename__ = "workspace"

    ...

    is_archived: Mapped[bool] = mapped_column(unique=False, default=False)

Upvotes: 3

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