Saving Link Model with Extra fields fails

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn’t find it.
• I searched the SQLModel documentation, with the integrated search.
• I already searched in Google “How to X in SQLModel” and didn’t find any information.
• I already read and followed all the tutorial in the docs and didn’t find an answer.
• I already checked if it is not related to SQLModel but to Pydantic.
• I already checked if it is not related to SQLModel but to SQLAlchemy.

Commit to Help

• I commit to help with one of those options 👆

Example Code

# Models

class AssemblyEPDLink(SQLModel, table=True):
    assembly_id: Optional[str] = Field(default=None, foreign_key="assembly.id", primary_key=True)
    epd_id: Optional[str] = Field(default=None, foreign_key="epd.id", primary_key=True)
    conversion_factor: float = 1.0

    assembly: "Assembly" = Relationship(back_populates="layer_links")
    epd: "EPD" = Relationship(back_populates="assembly_links")


class Assembly(SQLModel, table=True):
    """Assembly database class"""

    id: Optional[str] = Field(default_factory=string_uuid, primary_key=True)
    name: str = Field(index=True)
    category: str
    life_time: float = 50
    meta_fields: dict = Field(default=dict, sa_column=Column(JSON), nullable=False)
    unit: str = "M2"
    conversion_factor: float = 1.0

    layer_links: List[AssemblyEPDLink] = Relationship(back_populates="assembly")


class EPD(SQLModel, table=True):
    """EPD database class"""

    id: Optional[str] = Field(default_factory=string_uuid, primary_key=True)
    name: str = Field(index=True)
    category: str
    gwp_by_phases: dict = Field(default=dict, sa_column=Column(JSON), nullable=False)
    version: str
    expiration_date: date
    date_updated: date
    source: str

    assembly_links: List[AssemblyEPDLink] = Relationship(back_populates="epd")

# Strawberry Mutation
@strawberry.type
class Mutation:
    @strawberry.mutation(permission_classes=[IsAuthenticated])
    async def add_assembly(
        self,
        info: Info,
        name: str,
        category: str,
        life_time: float | None = 50,
        meta_fields: Optional[JSON] = None,
        layers: Optional[JSON] = None,
        conversion_factor: float | None = 1,
    ) -> GraphQLAssembly:

        if meta_fields is None:
            meta_fields = {}

        session = info.context.get("session")

        assembly = Assembly(
            name=name,
            category=category,
            life_time=life_time,
            conversion_factor=conversion_factor,
            meta_fields=meta_fields,
        )

        if layers:
            query = select(EPD).where(col(EPD.id).in_([layer.get("id") for layer in layers]))
            epds = await session.exec(query)
            epds = epds.all()

            for epd in epds:
                link = AssemblyEPDLink(assembly=assembly, epd=epd, conversion_factor=2)
                session.add(link)
        else:
            session.add(assembly)
            
        await session.commit()
        await session.refresh(assembly)

        return assembly

Description

• I start my test
• Set up a blank database and run SQLModel.metadata.create_all(bind=engine)
• I create three EPDs and save them to the database
• Then I post a new mutation to create a new Assembly with those EPDs in “layers”
• When I try to commit the AssemblyEPDLink to the session the database throws an error:
  • 'asyncpg.exceptions.NotNullViolationError': null value in column "assembly_id" of relation "assemblyepdlink" violates not-null constraint

Operating System

Linux

Operating System Details

Ubuntu 22.04

SQLModel Version

0.0.6

Python Version

3.10

Additional Context

I have tried to follow the steps outlined in the docs, adapted to my situation, but somehow the link model doesn’t want to save to the database.

When I create an Assembly without a link model everything works fine.

I have a setup with FastAPI, Strawberry, SQLModel and postgres.

[ocni-dtu]

@arjunkayalmoni you should just pin the version of sqlalchemy. You can do that by installing sqlalchemy as the right version and Poetry will take care of resolving the dependencies of SQLModel

[fullstack-spiderman]

Thank you @ocni-dtu, yes I done that already with a suggestion by my co-worker, and it indeed worked… thank you again… 😃