diff --git a/app/Http/Admin/Services/Article.php b/app/Http/Admin/Services/Article.php
index 0b8dd5ae..9f516762 100644
--- a/app/Http/Admin/Services/Article.php
+++ b/app/Http/Admin/Services/Article.php
@@ -199,9 +199,8 @@ class Article extends Service
             $data['published'] = $validator->checkPublishStatus($post['published']);
         }
 
-        if (isset($post['category_id']) && !empty($post['category_id'])) {
-            $category = $validator->checkCategory($post['category_id']);
-            $data['category_id'] = $category->id;
+        if (isset($post['category_id'])) {
+            $data['category_id'] = $validator->checkCategoryId($post['category_id']);
         }
 
         if (isset($post['xm_tag_ids'])) {
diff --git a/app/Http/Admin/Services/Help.php b/app/Http/Admin/Services/Help.php
index 0a681b20..2fde91de 100644
--- a/app/Http/Admin/Services/Help.php
+++ b/app/Http/Admin/Services/Help.php
@@ -63,12 +63,10 @@ class Help extends Service
 
         $data = [];
 
-        $category = $validator->checkCategory($post['category_id']);
-
         $data['title'] = $validator->checkTitle($post['title']);
         $data['content'] = $validator->checkContent($post['content']);
         $data['priority'] = $validator->checkPriority($post['priority']);
-        $data['category_id'] = $category->id;
+        $data['category_id'] = $validator->checkCategoryId($post['category_id']);
 
         $help = new HelpModel();
 
@@ -88,8 +86,7 @@ class Help extends Service
         $data = [];
 
         if (isset($post['category_id'])) {
-            $category = $validator->checkCategory($post['category_id']);
-            $data['category_id'] = $category->id;
+            $data['category_id'] = $validator->checkCategoryId($post['category_id']);
         }
 
         if (isset($post['title'])) {
diff --git a/app/Http/Admin/Services/Question.php b/app/Http/Admin/Services/Question.php
index 87ca6273..5dd98be7 100644
--- a/app/Http/Admin/Services/Question.php
+++ b/app/Http/Admin/Services/Question.php
@@ -186,9 +186,8 @@ class Question extends Service
             $data['published'] = $validator->checkPublishStatus($post['published']);
         }
 
-        if (isset($post['category_id']) && !empty($post['category_id'])) {
-            $category = $validator->checkCategory($post['category_id']);
-            $data['category_id'] = $category->id;
+        if (isset($post['category_id'])) {
+            $data['category_id'] = $validator->checkCategoryId($post['category_id']);
         }
 
         if (isset($post['xm_tag_ids'])) {
diff --git a/app/Services/Logic/Article/ArticleDataTrait.php b/app/Services/Logic/Article/ArticleDataTrait.php
index 5128c79f..73ceb94a 100644
--- a/app/Services/Logic/Article/ArticleDataTrait.php
+++ b/app/Services/Logic/Article/ArticleDataTrait.php
@@ -34,8 +34,7 @@ trait ArticleDataTrait
         $data['content'] = $validator->checkContent($post['content']);
 
         if (isset($post['category_id'])) {
-            $category = $validator->checkCategory($post['category_id']);
-            $data['category_id'] = $category->id;
+            $data['category_id'] = $validator->checkCategoryId($post['category_id']);
         }
 
         if (isset($post['source_type'])) {
diff --git a/app/Services/Logic/Question/QuestionDataTrait.php b/app/Services/Logic/Question/QuestionDataTrait.php
index 66a13906..fc73362b 100644
--- a/app/Services/Logic/Question/QuestionDataTrait.php
+++ b/app/Services/Logic/Question/QuestionDataTrait.php
@@ -33,8 +33,7 @@ trait QuestionDataTrait
         $data['content'] = $validator->checkContent($post['content']);
 
         if (isset($post['category_id'])) {
-            $category = $validator->checkCategory($post['category_id']);
-            $data['category_id'] = $category->id;
+            $data['category_id'] = $validator->checkCategoryId($post['category_id']);
         }
 
         if (isset($post['closed'])) {
diff --git a/app/Validators/Article.php b/app/Validators/Article.php
index 2d29ec76..cbbe4acc 100644
--- a/app/Validators/Article.php
+++ b/app/Validators/Article.php
@@ -66,11 +66,17 @@ class Article extends Validator
         }
     }
 
-    public function checkCategory($id)
+    public function checkCategoryId($id)
     {
-        $validator = new Category();
+        $result = 0;
 
-        return $validator->checkCategory($id);
+        if ($id > 0) {
+            $validator = new Category();
+            $category = $validator->checkCategory($id);
+            $result = $category->id;
+        }
+
+        return $result;
     }
 
     public function checkTitle($title)
diff --git a/app/Validators/Course.php b/app/Validators/Course.php
index 2a3ad61c..292c3c02 100644
--- a/app/Validators/Course.php
+++ b/app/Validators/Course.php
@@ -68,24 +68,28 @@ class Course extends Validator
 
     public function checkCategoryId($id)
     {
+        $result = 0;
+
         if ($id > 0) {
             $validator = new Category();
             $category = $validator->checkCategory($id);
-            return $category->id;
-        } else {
-            return 0;
+            $result = $category->id;
         }
+
+        return $result;
     }
 
     public function checkTeacherId($id)
     {
+        $result = 0;
+
         if ($id > 0) {
             $validator = new User();
             $user = $validator->checkTeacher($id);
-            return $user->id;
-        } else {
-            return 0;
+            $result = $user->id;
         }
+
+        return $result;
     }
 
     public function checkModel($model)
diff --git a/app/Validators/Help.php b/app/Validators/Help.php
index 63b715f7..e160573c 100644
--- a/app/Validators/Help.php
+++ b/app/Validators/Help.php
@@ -27,11 +27,17 @@ class Help extends Validator
         return $help;
     }
 
-    public function checkCategory($id)
+    public function checkCategoryId($id)
     {
-        $validator = new Category();
+        $result = 0;
 
-        return $validator->checkCategory($id);
+        if ($id > 0) {
+            $validator = new Category();
+            $category = $validator->checkCategory($id);
+            $result = $category->id;
+        }
+
+        return $result;
     }
 
     public function checkTitle($title)
diff --git a/app/Validators/Question.php b/app/Validators/Question.php
index 28ac33ad..e6099cd7 100644
--- a/app/Validators/Question.php
+++ b/app/Validators/Question.php
@@ -65,11 +65,17 @@ class Question extends Validator
         }
     }
 
-    public function checkCategory($id)
+    public function checkCategoryId($id)
     {
-        $validator = new Category();
+        $result = 0;
 
-        return $validator->checkCategory($id);
+        if ($id > 0) {
+            $validator = new Category();
+            $category = $validator->checkCategory($id);
+            $result = $category->id;
+        }
+
+        return $result;
     }
 
     public function checkTitle($title)