diff --git a/database/migrations/2026_01_03_090439_add_foreign_key_invoice_master_id_column_to_alert_mail_rules.php b/database/migrations/2026_01_03_090439_add_foreign_key_invoice_master_id_column_to_alert_mail_rules.php
new file mode 100644
index 0000000..0b67578
--- /dev/null
+++ b/database/migrations/2026_01_03_090439_add_foreign_key_invoice_master_id_column_to_alert_mail_rules.php
@@ -0,0 +1,33 @@
+<?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
+    {
+        $sql = <<<'SQL'
+            ALTER TABLE alert_mail_rules
+            ADD COLUMN invoice_master_id BIGINT DEFAULT NULL,
+            ADD CONSTRAINT invoice_masters_invoice_master_id_fkey
+            FOREIGN KEY (invoice_master_id) REFERENCES invoice_masters(id);
+        SQL;
+
+        DB::statement($sql);
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        // Schema::table('alert_mail_rules', function (Blueprint $table) {
+        //     //
+        // });
+    }
+};