Question to ForeignKeyField

[amrap030]

Hello, I need some help on the following:

I have an Event Model and an Account Model. When I want to create a new Event, I would like to store at the same time in the Account Model the reference to the event. from_ is the Account who initiated the event and to_ is the Account who received the event. However, this only works when I set the related_name to different names. Is there a way to get around this?

class Event(Model):
    id = fields.BigIntField(pk=True)
    from_ = fields.ForeignKeyField('models.Account', 'events', null=True, index=True)
    to_ = fields.ForeignKeyField('models.Account', 'events', null=True, index=True)
    event_type = fields.CharEnumField(EventType, default=EventType.unspecified)
    price = fields.BigIntField(null=True)
    timestamp = fields.DatetimeField()

[agammann]

related_name names the reverse attribute on Account. Your two fields would both try to define Account.events, but one means “events I sent” and the other means “events I received.” Give those roles separate names:

from_ = fields.ForeignKeyField(
    "models.Account", related_name="sent_events", null=True
)
to_ = fields.ForeignKeyField(
    "models.Account", related_name="received_events", null=True
)

Then query either direction:

sent = await account.sent_events.all()
received = await account.received_events.all()

If you want one list containing both roles, query Event directly:

from tortoise.expressions import Q

events = await Event.filter(Q(from_=account) | Q(to_=account))

Creating the event stores the foreign key IDs on the event row; you do not need a separate update to the account row to populate its reverse relations. I tested this with Tortoise ORM 1.1.8 and SQLite, including an event where the sender and recipient are the same account: the combined query returned that event once.

If you do not need reverse attributes at all, related_name=False disables their creation. See the ForeignKeyField reference.