How to perform a related object create

[hgalytoby]

Hi, I’m trying to figure out how to create a record with a related object using FastCRUD.

DBModel

class BaseSQL(DeclarativeBase):
    __abstract__ = True

    @declared_attr.directive
    def id(cls) -> Mapped[str]:
        return mapped_column(String(36), primary_key=True, default=lambda: str(uuid4()))

    @declared_attr.directive
    def created_at(cls) -> Mapped[datetime]:
        return mapped_column(
            DateTime(timezone=True),
            default=lambda: datetime.now(timezone.utc),
            nullable=False,
        )

    @declared_attr.directive
    def updated_at(cls) -> Mapped[datetime]:
        return mapped_column(
            DateTime(timezone=True),
            nullable=True,
            onupdate=lambda: datetime.now(timezone.utc),
        )

class CrawlerAccountOAuthSQL(BaseSQL):
    ...
    oauth: Mapped["CrawlerAccountOAuthSQL | None"] = relationship(
        back_populates="crawler_account",
        uselist=False,
        cascade="all, delete-orphan",
    )
    
class CrawlerAccountOAuthSQL(BaseSQL):
    ...
    crawler_account: Mapped["CrawlerAccountSQL"] = relationship(
        back_populates="oauth",
    )

With plain SQLAlchemy + async session, I can create a CrawlerAccountSQL along with its related CrawlerAccountOAuthSQL like this:

async with async_session_maker() as session:
    session.add(
        CrawlerAccountSQL(
            account="[email protected]",
            password="123",
            status=CrawlerAccountStatusEnum.ACTIVE,
            oauth=CrawlerAccountOAuthSQL(
                oauth_name="google",
                account_email="[email protected]",
                account_password="[email protected]",
            ),
        )
    )
    await session.commit()

This works fine.

But when I try to do the same thing using FastCRUD, I get an error:

class CrawlerAccountOAuthCreate(BaseModel): 
    oauth_name: str 
    account_email: EmailStr
    account_password: str


class CrawlerAccountSQLCreate(BaseModel):
    account: str    
    comment: str | None
    proxy_id: str | None
    password: str
    status: CrawlerAccountStatusEnum
    oauth: CrawlerAccountOAuthCreate


crud = FastCRUD(model=CrawlerAccountSQL)

await crud.create(
    db=session,
    object=CrawlerAccountSQLCreate(
        account="[email protected]",
        password="123",
        proxy_id=None,
        comment="",
        oauth=CrawlerAccountOAuthDBCreate(
            oauth_name="google",
            account_email="[email protected]",
            account_password="[email protected]",
        ),
    ),
)

This raises:

AttributeError: 'dict' object has no attribute '_sa_instance_state'

Is it not possible to perform a relational create? Do I have to insert them separately instead?

[igorbenav]

Hey @hgalytoby!
Currently it's not supported, but it's actually a good issue, I'll convert