diff --git a/app/Http/Requests/Admin/Manage/CourseClassRequest.php b/app/Http/Requests/Admin/Manage/CourseClassRequest.php
index 3b12ce1..71000d5 100644
--- a/app/Http/Requests/Admin/Manage/CourseClassRequest.php
+++ b/app/Http/Requests/Admin/Manage/CourseClassRequest.php
@@ -23,7 +23,7 @@ public function rules(): array
             'lecturer_id' => [
                 'required',
                 'integer',
-                Rule::exists('lecturers', 'id')->where('department_id', $departmentId),
+                Rule::exists('lecturer_department', 'lecturer_id')->where('department_id', $departmentId),
             ],
             'academic_term_id' => ['required', 'integer', Rule::exists('academic_terms', 'id')],
             'method' => ['nullable', 'string', Rule::in(ClassMethod::values())],
diff --git a/database/seeders/CourseClassSeeder.php b/database/seeders/CourseClassSeeder.php
index 2cb14a1..9caa3ba 100644
--- a/database/seeders/CourseClassSeeder.php
+++ b/database/seeders/CourseClassSeeder.php
@@ -2,30 +2,39 @@
 
 namespace Database\Seeders;
 
+use App\Enums\ClassMethod;
+use App\Models\AcademicTerm;
+use App\Models\Course;
 use App\Models\CourseClass;
+use App\Models\Lecturer;
 use Illuminate\Database\Seeder;
 
 class CourseClassSeeder extends Seeder
 {
     public function run(): void
     {
-        CourseClass::insert([
-            [
-                'course_id' => 1,
-                'lecturer_id' => 1,
-                'academic_term_id' => 2,
-                'method' => 'hybrid',
-                'created_at' => '2026-01-10 08:00:00',
-                'updated_at' => '2026-01-10 08:00:00',
-            ],
-            [
-                'course_id' => 2,
-                'lecturer_id' => 2,
-                'academic_term_id' => 2,
-                'method' => 'offline',
-                'created_at' => '2026-01-10 08:00:00',
-                'updated_at' => '2026-01-10 08:00:00',
-            ],
-        ]);
+        $academicTermId = AcademicTerm::where('is_active', true)->value('id')
+            ?? AcademicTerm::query()->value('id');
+
+        if (! $academicTermId) {
+            return;
+        }
+
+        Course::all()->each(function (Course $course) use ($academicTermId) {
+            $lecturer = Lecturer::whereHas('departments', fn ($q) => $q->where('departments.id', $course->department_id))
+                ->inRandomOrder()
+                ->first();
+
+            if (! $lecturer) {
+                return;
+            }
+
+            CourseClass::create([
+                'course_id' => $course->id,
+                'lecturer_id' => $lecturer->id,
+                'academic_term_id' => $academicTermId,
+                'method' => fake()->randomElement(ClassMethod::values()),
+            ]);
+        });
     }
 }