How can I fix autoincrement returning null

[Inkapa]

Hello, I'm trying to use ormar to make a very simple API for a Quiz app.

My model looks like this:

My issue stems from the create_quiz endpoint (see below). When creating a new quiz with its questions and answers, despite having the id primary key field of the question and answer tables set to auto-increment, if I don't specify them in the POST data, the ids of the questions and answers will be set to null.

If I then try to get the quiz with its id, the list of linked questions (and by such answers) will be empty.

Here's an example of the data passed to the create_quiz endpoint:

{
  "title": "Example",
  "questions": [
    {
      "question": "A question",
      "answers": [
        {
          "text": "Answer 1",
          "correct": true
        },
        {
          "text": "Answer 2",
          "correct": false
        },
        {
          "text": "Answer 3",
          "correct": false
        },
        {
          "text": "Answer 4",
          "correct": false
        }
      ]
    }
  ]
}

And here's what it returns

{
  "id": "5f944f7ee90e4d",
  "title": "Example",
  "questions": [
    {
      "id": null,
      "question": "A question",
      "answers": [
        {
          "id": null,
          "text": "Answer 1",
          "correct": true
        },
        {
          "id": null,
          "text": "Answer 2",
          "correct": false
        },
        {
          "id": null,
          "text": "Answer 3",
          "correct": false
        },
        {
          "id": null,
          "text": "Answer 4",
          "correct": false
        }
      ],
      "quiz": {
        "id": "5f944f7ee90e4d",
        "title": "Example"
      }
    }
  ]
}

The quiz is created without any problems, but the questions and answers aren't accessible

My code is as follows:

import databases
import sqlalchemy
import uvicorn
from fastapi import FastAPI, HTTPException
import secrets
import random

import ormar
from ormar import Integer, String, Boolean, ForeignKey

app = FastAPI()
metadata = sqlalchemy.MetaData()
database = databases.Database(url)
app.state.database = database

@app.on_event("startup")
async def startup() -> None:
    database_ = app.state.database
    if not database_.is_connected:
        await database_.connect()


@app.on_event("shutdown")
async def shutdown() -> None:
    database_ = app.state.database
    if database_.is_connected:
        await database_.disconnect()


class Quiz(ormar.Model):
    class Meta:
        tablename = "quiz"
        database = database
        metadata = metadata

    id: str = String(primary_key=True, index=True, max_length=15, default='')
    title: str = String(max_length=100, nullable=False)


class Question(ormar.Model):
    class Meta:
        tablename = "question"
        database = database
        metadata = metadata

    id: int = Integer(primary_key=True, autoincrement=True)
    question: str = String(max_length=150, nullable=False)
    quiz: Quiz = ForeignKey(Quiz)


class Answer(ormar.Model):
    class Meta:
        tablename = "answer"
        database = database
        metadata = metadata

    id: int = Integer(primary_key=True, autoincrement=True)
    text: str = String(max_length=100, nullable=False)
    correct: bool = Boolean(nullable=False)
    question: Question = ForeignKey(Question)


@app.get("/quiz/random", response_model=Quiz)
async def get_random_quiz():
    # ormar doesn't yet support func.random() in order_by
    quizs = await Quiz.objects.all()
    return random.choice(quizs)


@app.get("/quiz/{quiz_id}", response_model=Quiz)
async def get_quiz_with_id(quiz_id: str):
    try:
        quiz = await Quiz.objects.get(pk=quiz_id)
    except ormar.exceptions.NoMatch:
        raise HTTPException(status_code=404, detail="Quiz not found")
    return quiz


@app.post("/quiz/create", response_model=Quiz)
async def create_quiz(quiz: Quiz):
    # random hex id for the quiz
    new_id = secrets.token_hex(7)
    while True:
        # Verify that the generated hex id isn't already assigned
        try:
            await Quiz.objects.get(pk=new_id)
            new_id = secrets.token_hex(7)
        except ormar.exceptions.NoMatch:
            break
    quiz.id = new_id
    await quiz.save()
    return quiz


if __name__ == "__main__":
    # Create DB tables on first run
    # engine = sqlalchemy.create_engine(url)
    # metadata.create_all(engine)

    # to play with API run the script and visit http://127.0.0.1:8000/docs
    uvicorn.run(app, host="127.0.0.1", port=8000)

[collerek]

save saves only the main model, to save the whole tree including relations you need to use save_related https://collerek.github.io/ormar/models/methods/#save_related.

Otherwise, child models are not saved and you get back unsaved data (that's why they are missing the pk column)

[Inkapa]

Works like a charm, thank you!