I'm currently exploring peewee ORM and in order to make some tests I've defined two simple databases with three tables as follow

I then defined the peewee models into a single file

from playhouse.shortcuts import model_to_dict
import peewee as pw
import json

public_database = pw.MySQLDatabase(None)
private_database = pw.MySQLDatabase(None)

class CommonModel(pw.Model):

    def json(self, recurse=False):
        return model_to_dict(self, recurse=recurse)

    def __str__(self):
        return json.dumps(self.json())

class PublicDatabaseModel(CommonModel):
    class Meta:
        database = public_database

class PrivateDatabaseModel(CommonModel):
    class Meta:
        database = private_database

class User(PrivateDatabaseModel):
    class Meta:
        db_table = "users"
    
    id = pw.AutoField(primary_key=True)
    firstname = pw.CharField()
    lastname = pw.CharField()
    email = pw.CharField()

class Character(PublicDatabaseModel):
    class Meta:
        db_table = "characters"

    id = pw.AutoField(primary_key=True)
    name = pw.CharField()

    user = pw.ForeignKeyField(User)

class Item(PublicDatabaseModel):
    class Meta:
        db_table = "items"

    id = pw.AutoField(primary_key=True)
    name = pw.CharField()

    character = pw.ForeignKeyField(Character)

I can then define database connections into a testing file

import peewee_models as models

models.private_database.init(
    "test_database_private",
    host="localhost",
    user="root",
    password="password",
    port=3306
)
models.public_database.init(
    "test_database_public",
    host="localhost",
    user="root",
    password="password",
    port=3306
)

characters = models.Character.select()
for character in characters:
    print("-------------------")
    print(f"Character : {character}")
    print(f"Character.id : {character.id}")
    print(f"Character.name : {character.name}")
    print(f"Character.user_id : {character.user_id}")
    print(f"Character.user : {character.user}")

The issue I have is that I can't find a way to render models as JSON with the foreign_key name as a key, the key name is always the name of the associated relationship

-------------------
Character : {"id": 1, "name": "User1_Char1", "user": 1}
Character.id : 1
Character.name : User1_Char1
Character.user_id : 1
Character.user : {"id": 1, "firstname": "user1_firstname", "lastname": "user1_lastname", "email": "[email protected]"}
-------------------
Character : {"id": 2, "name": "User1_Char2", "user": 1}
Character.id : 2
Character.name : User1_Char2
Character.user_id : 1
Character.user : {"id": 1, "firstname": "user1_firstname", "lastname": "user1_lastname", "email": "[email protected]"}

For example I'd like the Character class JSON to be {"id": 2, "name": "User1_Char2", "user_id": 1} instead of {"id": 2, "name": "User1_Char2", "user": 1} but I can't find a way to achieve it.

I tried to change several ForeignKeyField class parameters such as object_id_name and related_name but nothing seems to change anything, even though the user_id attribute does exist in the class instance.

Does anyone know how to have the foreign_key name instead of the relationship name as JSON key ?