Fetch the manyTo* entity collections of parts with other part columns

This reduces the query count and should improve performance especially for big tables.

src/DataTables/Adapter/CustomORMAdapter.php

@@ -0,0 +1,81 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ * Copyright (C) 2019 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+namespace App\DataTables\Adapter;
+
+
+use Doctrine\ORM\Query;
+use Doctrine\ORM\QueryBuilder;
+use Omines\DataTablesBundle\Adapter\AdapterQuery;
+use Omines\DataTablesBundle\Adapter\Doctrine\ORMAdapter;
+use Omines\DataTablesBundle\Column\AbstractColumn;
+
+/**
+ * Override default ORM Adapter, to allow fetch joins (allow addSelect with ManyToOne Collections).
+ * This should improves performance for Part Tables.
+ * Based on: https://github.com/omines/datatables-bundle/blob/master/tests/Fixtures/AppBundle/DataTable/Adapter/CustomORMAdapter.php
+ * @package App\DataTables\Adapter
+ */
+class CustomORMAdapter extends ORMAdapter
+{
+    protected $hydrationMode;
+    public function configure(array $options)
+    {
+        parent::configure($options);
+        $this->hydrationMode = isset($options['hydrate']) ? $options['hydrate'] : Query::HYDRATE_OBJECT;
+    }
+    protected function prepareQuery(AdapterQuery $query)
+    {
+        parent::prepareQuery($query);
+        $query->setIdentifierPropertyPath(null);
+    }
+    /**
+     * @param AdapterQuery $query
+     * @return \Traversable
+     */
+    protected function getResults(AdapterQuery $query): \Traversable
+    {
+        /** @var QueryBuilder $builder */
+        $builder = $query->get('qb');
+        $state = $query->getState();
+        // Apply definitive view state for current 'page' of the table
+        foreach ($state->getOrderBy() as list($column, $direction)) {
+            /** @var AbstractColumn $column */
+            if ($column->isOrderable()) {
+                $builder->addOrderBy($column->getOrderField(), $direction);
+            }
+        }
+        if ($state->getLength() > 0) {
+            $builder
+                ->setFirstResult($state->getStart())
+                ->setMaxResults($state->getLength());
+        }
+        /*
+         * Use foreach instead of iterate to prevent group by from crashing
+         */
+        foreach ($builder->getQuery()->getResult($this->hydrationMode) as $result) {
+            /*
+             * Return everything instead of first element
+             */
+            yield $result;
+        }
+    }
+}