diff --git a/database/migrations/2026_11_03_102743_add_unique_plant_id_gr_number_to_gr_masters.php b/database/migrations/2026_11_03_102743_add_unique_plant_id_gr_number_to_gr_masters.php
new file mode 100644
index 00000000..383048a6
--- /dev/null
+++ b/database/migrations/2026_11_03_102743_add_unique_plant_id_gr_number_to_gr_masters.php
@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        $sql = <<<'SQL'
+            ALTER TABLE gr_masters
+            ADD CONSTRAINT gr_masters_plant_id_gr_number_key
+            UNIQUE (plant_id, gr_number)
+        SQL;
+
+        DB::statement($sql);
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        // Schema::table('gr_masters', function (Blueprint $table) {
+        //     //
+        // });
+    }
+};