diff --git a/database/migrations/2024_12_27_060234_create_studies_table.php b/database/migrations/2024_12_27_060234_create_studies_table.php
index 2cf9f88..f22a5a5 100644
--- a/database/migrations/2024_12_27_060234_create_studies_table.php
+++ b/database/migrations/2024_12_27_060234_create_studies_table.php
@@ -13,12 +13,12 @@ public function up(): void
     {
         Schema::create('studies', function (Blueprint $table) {
             $table->id();
-            $table->string('orthanc_uuid')->unique();
+            $table->string('orthanc_uuid')->unique()->index();
             $table->boolean('is_archived')->default(false);
             $table->unsignedTinyInteger('priority')->default(Priority::Routine);
 
-            $table->string('patient_id')->nullable();
             $table->string('patient_uuid')->nullable()->index();
+            $table->string('patient_id')->nullable();
             $table->string('patient_name');
             $table->string('patient_sex')->nullable();
             $table->date('patient_birthdate')->nullable();