Index: iknow-api/Data/AppDbContext.cs
===================================================================
--- iknow-api/Data/AppDbContext.cs	(revision 691f152bd55c9f383727616f191bbda6ee1abcfb)
+++ iknow-api/Data/AppDbContext.cs	(revision 61fd94e0458beeab4c9ce37f9b4b811cabf8d7ac)
@@ -14,5 +14,4 @@
         public DbSet<EnrollmentInfo> EnrollmentInfo { get; set; }
         public DbSet<RefreshToken> RefreshToken { get; set; }
-
         public DbSet<Subject> Subjects { get; set; }
         public DbSet<DependencySubject> DependencySubjects { get; set; }
@@ -20,4 +19,10 @@
         public DbSet<PassedSubject> PassedSubjects { get; set; }
         public DbSet<EnrolledSemesters> EnrolledSemesters { get; set; }
+        public DbSet<ActiveSemesters> ActiveSemesters { get; set; }
+        public DbSet<SemesterSubject> SemesterSubjects { get; set; }
+        public DbSet<MajorSubjects> MajorSubjects { get; set; }
+        public DbSet<UserDocuments> UserDocuments { get; set; }
+        public DbSet<Documents> Documents { get; set; }
+        public DbSet<Payment> Payments { get; set; }
 
 
@@ -92,16 +97,16 @@
             // -------------------------
             modelBuilder.Entity<Payment>()
-                .HasKey(ab => new { ab.UserId, ab.EnrollmentInfoId });
+                .HasKey(p => p.Id);
 
             modelBuilder.Entity<Payment>()
-                .HasOne(ab => ab.User)
-                .WithMany(a => a.EnrolledSemesters)
-                .HasForeignKey(ab => ab.UserId)
+                .HasOne(p => p.User)
+                .WithMany(u => u.EnrolledSemesters)
+                .HasForeignKey(p => p.UserId)
                 .OnDelete(DeleteBehavior.Cascade);
 
             modelBuilder.Entity<Payment>()
-                .HasOne(ab => ab.EnrolledSemesters)
-                .WithMany(b => b.Users)
-                .HasForeignKey(ab => ab.EnrollmentInfoId)
+                .HasOne(p => p.EnrolledSemesters)
+                .WithMany(es => es.Users)
+                .HasForeignKey(p => p.EnrollmentInfoId)
                 .OnDelete(DeleteBehavior.Cascade);
 
@@ -151,4 +156,13 @@
                 .HasForeignKey<PassedSubject>(ps => ps.SemesterSubjectId)
                 .OnDelete(DeleteBehavior.Cascade);
+
+            // -------------------------
+            // ActiveSemesters to EnrolledSemesters (one-to-many)
+            // -------------------------
+            modelBuilder.Entity<EnrolledSemesters>()
+                .HasOne(es => es.Semester)
+                .WithMany(a => a.EnrolledSemesters)
+                .HasForeignKey(es => es.Id)
+                .OnDelete(DeleteBehavior.Restrict);
         }