diff --git a/src/main/java/com/application/munera/data/Category.java b/src/main/java/com/application/munera/data/Category.java
index cb9b46b..6cbb74e 100644
--- a/src/main/java/com/application/munera/data/Category.java
+++ b/src/main/java/com/application/munera/data/Category.java
@@ -21,4 +21,7 @@ public class Category {
 
     @Column(name = "Description")
     private String description;
+
+    @Column(name = "userId", nullable = false, unique = true)
+    private Long userId;
 }
diff --git a/src/main/java/com/application/munera/data/Expense.java b/src/main/java/com/application/munera/data/Expense.java
index 0d75762..a424a9f 100644
--- a/src/main/java/com/application/munera/data/Expense.java
+++ b/src/main/java/com/application/munera/data/Expense.java
@@ -64,4 +64,7 @@ public class Expense {
     @Enumerated(EnumType.STRING)
     @Column(name = "expenseType", nullable = false)
     private ExpenseType expenseType;
+
+    @Column(name = "userId", nullable = false, unique = true)
+    private Long userId;
 }
\ No newline at end of file
diff --git a/src/main/java/com/application/munera/data/Person.java b/src/main/java/com/application/munera/data/Person.java
index f5a30e1..248b18f 100644
--- a/src/main/java/com/application/munera/data/Person.java
+++ b/src/main/java/com/application/munera/data/Person.java
@@ -49,7 +49,7 @@ public class Person {
     @Column(name = "Username", unique = true)
     private String username; // This field will link to the User entity
 
-    @Column(name = "UserId", unique = true)
+    @Column(name = "UserId", unique = true, nullable = false)
     private Long userId; // Reference to the User entity
 
     @Override
diff --git a/src/main/java/com/application/munera/services/ExpenseService.java b/src/main/java/com/application/munera/services/ExpenseService.java
index 88a375f..b75aeb3 100644
--- a/src/main/java/com/application/munera/services/ExpenseService.java
+++ b/src/main/java/com/application/munera/services/ExpenseService.java
@@ -146,6 +146,7 @@ public class ExpenseService {
      */
     public void update(Expense entity) {
         if (Boolean.TRUE.equals(entity.getIsPaid())) entity.setPaymentDate(LocalDate.now());
+        else entity.setPaymentDate(null);
         this.setExpenseType(entity);
         expenseRepository.save(entity);
     }