Keep login events after the user has been removed

Entity/LoginEntry.php

@@ -22,7 +22,6 @@ namespace vierbergenlars\AuthserverStatsBundle\Entity;
 
 use App\Entity\User;
 use Doctrine\ORM\Mapping as ORM;
-use Doctrine\ORM\Mapping\Column;
 
 /**
  * @ORM\Entity
@@ -42,6 +41,7 @@ class LoginEntry
 
     /**
      * @ORM\ManyToOne(targetEntity="App\Entity\User", fetch="EAGER")
+     * @ORM\JoinColumn(nullable=true)
      *
      * @var User
      */

Resources/migrations/VersionAuthserverStats20171102211018.php

@@ -0,0 +1,60 @@
+<?php
+/**
+ * Authserver, an OAuth2-based single-signon authentication provider written in PHP.
+ *
+ * Copyright (C) $today.date  Lars Vierbergen
+ *
+ * his program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+namespace Application\Migrations;
+
+use Doctrine\DBAL\Migrations\AbstractMigration;
+use Doctrine\DBAL\Schema\Schema;
+
+class VersionAuthserverStats20171102211018 extends AbstractMigration
+{
+
+    public function up(Schema $schema)
+    {
+        $loginEntry = $schema->getTable('vierbergenlars_stats_login_entry');
+
+        $loginEntry->removeForeignKey('vl_stats_le');
+        $loginEntry->getColumn('user_id')->setNotNull(false);
+
+        $loginEntry->addForeignKeyConstraint('auth_users', [
+            'user_id'
+        ], [
+            'id'
+        ], [
+            'onDelete' => 'SET NULL'
+        ], 'vl_stats_le');
+    }
+
+    public function down(Schema $schema)
+    {
+        $loginEntry = $schema->getTable('vierbergenlars_stats_login_entry');
+
+        $loginEntry->removeForeignKey('vl_stats_le');
+        $loginEntry->getColumn('user_id')->setNotNull(true);
+
+        $loginEntry->addForeignKeyConstraint('auth_users', [
+            'user_id'
+        ], [
+            'id'
+        ], [
+            'onDelete' => 'DELETE'
+        ], 'vl_stats_le');
+    }
+}
+