feat: split bills for one deal

models/billing.py

@@ -13,13 +13,13 @@ if TYPE_CHECKING:
 class CardBillRequest(BaseModel):
     __tablename__ = 'card_bill_requests'
 
+    id: Mapped[int] = mapped_column(primary_key=True)
+
     card_id: Mapped[int] = mapped_column(
         ForeignKey('cards.id'),
         nullable=False,
-        primary_key=True,
-        unique=True,
     )
-    card: Mapped['Card'] = relationship(back_populates='bill_request')
+    card: Mapped['Card'] = relationship(back_populates='bill_requests')
 
     created_at: Mapped[datetime.datetime] = mapped_column(nullable=False)
     paid: Mapped[bool] = mapped_column(nullable=False, default=False)
@@ -31,13 +31,13 @@ class CardBillRequest(BaseModel):
 class GroupBillRequest(BaseModel):
     __tablename__ = 'group_bill_requests'
 
+    id: Mapped[int] = mapped_column(primary_key=True)
+
     group_id: Mapped[int] = mapped_column(
         ForeignKey('card_groups.id'),
         nullable=False,
-        primary_key=True,
-        unique=True,
     )
-    group: Mapped['CardGroup'] = relationship(back_populates='bill_request')
+    group: Mapped['CardGroup'] = relationship(back_populates='bill_requests')
 
     created_at: Mapped[datetime.datetime] = mapped_column(nullable=False)
     paid: Mapped[bool] = mapped_column(nullable=False, default=False)

models/card.py

@@ -93,7 +93,11 @@ class Card(BaseModel):
         order_by="desc(CardProduct.product_id)"
     )
 
-    bill_request: Mapped[Optional['CardBillRequest']] = relationship(back_populates='card', lazy='joined')
+    bill_requests: Mapped[list['CardBillRequest']] = relationship(
+        back_populates='card',
+        lazy='selectin',
+        uselist=True,
+    )
 
     # module client
     client_id: Mapped[Optional[int]] = mapped_column(

models/card_group.py

@@ -25,9 +25,10 @@ class CardGroup(BaseModel):
         back_populates='group',
         secondary='card_relations'
     )
-    bill_request: Mapped[Optional['GroupBillRequest']] = relationship(
+    bill_requests: Mapped[list['GroupBillRequest']] = relationship(
         back_populates='group',
-        lazy='joined'
+        lazy='joined',
+        uselist=True,
     )