diff --git a/database/migrations/2016_08_30_084634_make_purchase_cost_nullable.php b/database/migrations/2016_08_30_084634_make_purchase_cost_nullable.php
index c4eef30aa8..241fa07269 100644
--- a/database/migrations/2016_08_30_084634_make_purchase_cost_nullable.php
+++ b/database/migrations/2016_08_30_084634_make_purchase_cost_nullable.php
@@ -12,6 +12,10 @@ class MakePurchaseCostNullable extends Migration
      */
     public function up()
     {
+
+        $platform = Schema::getConnection()->getDoctrineSchemaManager()->getDatabasePlatform();
+        $platform->registerDoctrineTypeMapping('enum', 'string');
+
         Schema::table('assets', function ($table) {
             $table->decimal('purchase_cost',8,2)->nullable()->default(null)->change();
         });