Create data for 1-M or M-M relatationship using List of IDs rather than List of objects

[petercinibulk]

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Example Code

from typing import List, Optional

from sqlmodel import Field, Relationship, Session, SQLModel, create_engine
from fastapi.encoders import jsonable_encoder


class Team(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str

    hero_ids: List[int] = Field(default=None, foreign_key="hero.id")  # Doesn't work
    heroes: List["Hero"] = Relationship(back_populates="team")


class Hero(SQLModel, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    name: str

    team_id: Optional[int] = Field(default=None, foreign_key="team.id")
    team: Optional[Team] = Relationship(back_populates="hero_ids")


class TeamCreate(SQLModel):
    name: str
    hero_ids: List[int]


def create_team(db: Session, obj_in: TeamCreate) -> Team:
    obj_in_data = jsonable_encoder(obj_in)
    db_obj = Team(**obj_in_data)
    db.add(db_obj)
    db.commit()
    db.refresh(db_obj)
    return db_obj


sqlite_file_name = "database.db"
sqlite_url = f"sqlite:///{sqlite_file_name}"

connect_args = {"check_same_thread": False}
engine = create_engine(sqlite_url, connect_args=connect_args)
SQLModel.metadata.drop_all(engine)
SQLModel.metadata.create_all(engine)

with Session(engine) as db:
    hero_1 = Hero(name="Hero1")
    hero_2 = Hero(name="Hero2")
    db.add(hero_1)
    db.add(hero_2)
    db.commit()
    db.refresh(hero_1)
    db.refresh(hero_2)

    team1 = TeamCreate(name="Team1", hero_ids=[hero_1.id, hero_2.id])
    team1 = create_team(db, team1)

    if len(team1.heroes) == 2:
        print("IT WORKED!")
    else:
        print(":'(")

Description

I posted this issue a while back #124 which I am basically asking again here. I originally closed the issue as that answer sufficed but now it recently resurfaced. One of the strong features of SQLModel is the relationship with pydantic. I use a lot of CRUD base models to automatically create CRUD operations for me. An example of this would be a more abstract version of the create_team function above. In the above example, something I want to be able to have TeamCreate model and create a Team entry using hero_ids instead of heroes.

A workaround is to manually load the heroes from their ids but then I would need another model inorder to have the create_team function work

Operating System

Linux

Operating System Details

Ubuntu

SQLModel Version

0.0.8

Python Version

Python 3.11.2

Additional Context

No response