diff --git a/database/migrations/2025_12_13_152631_migrate_products_materials_to_items.php b/database/migrations/2025_12_13_152631_migrate_products_materials_to_items.php
index 3f70e92..a59ce2d 100644
--- a/database/migrations/2025_12_13_152631_migrate_products_materials_to_items.php
+++ b/database/migrations/2025_12_13_152631_migrate_products_materials_to_items.php
@@ -22,17 +22,21 @@
      */
     public function up(): void
     {
-        // ID 매핑 테이블 생성
-        Schema::create('item_id_mappings', function (Blueprint $table) {
-            $table->id();
-            $table->string('source_table', 20)->comment('products or materials');
-            $table->unsignedBigInteger('source_id')->comment('원본 테이블 ID');
-            $table->unsignedBigInteger('item_id')->comment('items 테이블 ID');
-            $table->timestamps();
+        // ID 매핑 테이블 생성 (없으면 생성, 있으면 초기화)
+        if (! Schema::hasTable('item_id_mappings')) {
+            Schema::create('item_id_mappings', function (Blueprint $table) {
+                $table->id();
+                $table->string('source_table', 20)->comment('products or materials');
+                $table->unsignedBigInteger('source_id')->comment('원본 테이블 ID');
+                $table->unsignedBigInteger('item_id')->comment('items 테이블 ID');
+                $table->timestamps();
 
-            $table->unique(['source_table', 'source_id']);
-            $table->index('item_id');
-        });
+                $table->unique(['source_table', 'source_id']);
+                $table->index('item_id');
+            });
+        } else {
+            DB::table('item_id_mappings')->truncate();
+        }
 
         $productCount = 0;
         $materialCount = 0;
@@ -107,11 +111,17 @@ public function up(): void
             ->get();
 
         foreach ($materials as $material) {
+            // NULL 코드 처리: 자동 생성
+            $code = $material->material_code;
+            if (empty($code)) {
+                $code = sprintf('%s-%06d', $material->material_type, $material->id);
+            }
+
             // items 테이블에 삽입
             $itemId = DB::table('items')->insertGetId([
                 'tenant_id' => $material->tenant_id,
                 'item_type' => $material->material_type,
-                'code' => $material->material_code,
+                'code' => $code,
                 'name' => $material->name,
                 'unit' => $material->unit,
                 'category_id' => $material->category_id,