diff --git a/dibbler/models/Purchase.py b/dibbler/models/Purchase.py
index 42c4c52..be6873d 100644
--- a/dibbler/models/Purchase.py
+++ b/dibbler/models/Purchase.py
@@ -1,8 +1,8 @@
 from __future__ import annotations
-from typing import TYPE_CHECKING
 
-from datetime import datetime
 import math
+from datetime import datetime
+from typing import TYPE_CHECKING
 
 from sqlalchemy import (
     DateTime,
@@ -29,7 +29,8 @@ class Purchase(Base):
     price: Mapped[int] = mapped_column(Integer)
 
     transactions: Mapped[set[Transaction]] = relationship(
-        back_populates="purchase", order_by="Transaction.user_name"
+        back_populates="purchase",
+        order_by=Transaction.user_name,
     )
     entries: Mapped[set[PurchaseEntry]] = relationship(back_populates="purchase")
 
diff --git a/dibbler/models/PurchaseEntry.py b/dibbler/models/PurchaseEntry.py
index 8484b32..4989473 100644
--- a/dibbler/models/PurchaseEntry.py
+++ b/dibbler/models/PurchaseEntry.py
@@ -27,8 +27,8 @@ class PurchaseEntry(Base):
     product_id: Mapped[int] = mapped_column(ForeignKey("products.product_id"))
     purchase_id: Mapped[int] = mapped_column(ForeignKey("purchases.id"))
 
-    product: Mapped[Product] = relationship(lazy="joined")
-    purchase: Mapped[Purchase] = relationship(lazy="joined")
+    product: Mapped[Product] = relationship(back_populates='purchases', lazy="joined")
+    purchase: Mapped[Purchase] = relationship(back_populates='entries', lazy="joined")
 
     def __init__(self, purchase, product, amount):
         self.product = product
diff --git a/dibbler/models/Transaction.py b/dibbler/models/Transaction.py
index 6c509ef..8a3626b 100644
--- a/dibbler/models/Transaction.py
+++ b/dibbler/models/Transaction.py
@@ -36,7 +36,7 @@ class Transaction(Base):
     purchase_id: Mapped[int | None] = mapped_column(ForeignKey("purchases.id"))
 
     user: Mapped[User] = relationship(lazy="joined")
-    purchase: Mapped[Purchase] = relationship(lazy="joined")
+    purchase: Mapped[Purchase] = relationship(back_populates='transactions', lazy="joined")
 
     def __init__(
         self,
diff --git a/dibbler/models/User.py b/dibbler/models/User.py
index 1fd91c1..2409d8d 100644
--- a/dibbler/models/User.py
+++ b/dibbler/models/User.py
@@ -1,4 +1,5 @@
 from __future__ import annotations
+
 from typing import TYPE_CHECKING
 
 from sqlalchemy import (
@@ -14,19 +15,22 @@ from sqlalchemy.orm import (
 from .Base import Base
 
 if TYPE_CHECKING:
-    from .UserProducts import UserProducts
     from .Transaction import Transaction
+    from .UserProducts import UserProducts
 
 
 class User(Base):
     __tablename__ = "users"
     name: Mapped[str] = mapped_column(String(10), primary_key=True)
-    credit: Mapped[str] = mapped_column(Integer)
+    credit: Mapped[int] = mapped_column(Integer)
     card: Mapped[str | None] = mapped_column(String(20))
     rfid: Mapped[str | None] = mapped_column(String(20))
 
     products: Mapped[list[UserProducts]] = relationship(back_populates="user")
-    transactions: Mapped[list[Transaction]] = relationship(back_populates="user")
+    transactions: Mapped[list[Transaction]] = relationship(
+        back_populates="user",
+        order_by="Transaction.time",
+    )
 
     name_re = r"[a-z]+"
     card_re = r"(([Nn][Tt][Nn][Uu])?[0-9]+)?"
diff --git a/dibbler/models/UserProducts.py b/dibbler/models/UserProducts.py
index 17a8f13..a3448d9 100644
--- a/dibbler/models/UserProducts.py
+++ b/dibbler/models/UserProducts.py
@@ -27,5 +27,5 @@ class UserProducts(Base):
     count: Mapped[int] = mapped_column(Integer)
     sign: Mapped[int] = mapped_column(Integer)
 
-    user: Mapped[User] = relationship()
-    product: Mapped[Product] = relationship()
+    user: Mapped[User] = relationship(back_populates="products")
+    product: Mapped[Product] = relationship(back_populates="users")