diff --git a/Annotation/ImportExclude.php b/Annotation/ImportExclude.php
index a99ce7c..5a69f2f 100644
--- a/Annotation/ImportExclude.php
+++ b/Annotation/ImportExclude.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/AvroCsvBundle.php b/AvroCsvBundle.php
index 4b6658a..4b58a6f 100644
--- a/AvroCsvBundle.php
+++ b/AvroCsvBundle.php
@@ -1,5 +1,10 @@
 <?php
 
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Avro\CsvBundle;
 
 use Symfony\Component\HttpKernel\Bundle\Bundle;
diff --git a/AvroCsvEvents.php b/AvroCsvEvents.php
index 5c0d472..59f662c 100644
--- a/AvroCsvEvents.php
+++ b/AvroCsvEvents.php
@@ -46,4 +46,20 @@ final class AvroCsvEvents
      * @Event("Avro\CsvBundle\Event\RowErrorEvent")
      */
     const ROW_ERROR = 'avro_csv.row_error';
+    /**
+     * The ASSOCIATION_FIELD event occurs when the importer hits an association field.
+     *
+     * This event allows you to implement handling of the association.
+     *
+     * @Event("Avro\CsvBundle\Event\AssociationFieldEvent")
+     */
+    const ASSOCIATION_FIELD = 'avro_csv.association_field';
+    /**
+     * The CUSTOM_FIELD event occurs when the importer hits an import field that is not recognized by Doctrine.
+     *
+     * This event allows you to implement handling of these fields.
+     *
+     * @Event("Avro\CsvBundle\Event\CustomFieldEvent")
+     */
+    const CUSTOM_FIELD = 'avro_csv.custom_field';
 }
diff --git a/Controller/ExportController.php b/Controller/ExportController.php
index 47b0d40..e4a6f3a 100644
--- a/Controller/ExportController.php
+++ b/Controller/ExportController.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Controller/ImportController.php b/Controller/ImportController.php
index 9d62c0c..63553cd 100644
--- a/Controller/ImportController.php
+++ b/Controller/ImportController.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -87,7 +87,7 @@ public function uploadAction($alias)
      * Move the csv file to a temp dir and get the user to map the fields.
      *
      * @param Request $request The request
-     * @param string $alias The objects alias
+     * @param string  $alias   The objects alias
      *
      * @return Response
      */
@@ -118,7 +118,7 @@ public function mappingAction(Request $request, $alias)
 
                 // Recreate form and create proper fields child for each header
                 $form = $this->formFactory->create(ImportFormType::class, null, ['field_choices' => $fieldChoices]);
-                $form->get('fields')->setData(array_fill_keys((array)$headers, null));
+                $form->get('fields')->setData(array_fill_keys((array) $headers, null));
                 $form->handleRequest($request);
 
                 $rows = $this->reader->getRows($this->container->getParameter('avro_csv.sample_count'));
@@ -129,7 +129,7 @@ public function mappingAction(Request $request, $alias)
                         [
                             'form' => $form->createView(),
                             'alias' => $alias,
-                            'headers' => array_combine((array)$headers, (array)$fileHeaders),
+                            'headers' => array_combine((array) $headers, (array) $fileHeaders),
                             'headersJson' => json_encode(
                                 $this->caseConverter->toTitleCase($fileHeaders),
                                 JSON_FORCE_OBJECT
@@ -152,7 +152,7 @@ public function mappingAction(Request $request, $alias)
      * Previews the uploaded csv and allows the user to map the fields.
      *
      * @param Request $request The request
-     * @param string $alias The objects alias
+     * @param string  $alias   The objects alias
      *
      * @return Response
      */
@@ -184,7 +184,7 @@ public function processAction(Request $request, $alias)
 
                 $request->getSession()->getFlashBag()->set(
                     'success',
-                    $this->importer->getImportCount() . ' items imported. ' . $this->importer->getImportErrors() . ' errors.'
+                    $this->importer->getImportCount().' items imported. '.$this->importer->getImportErrors().' errors.'
                 );
             } else {
                 $request->getSession()->getFlashBag()->set('error', 'Import failed. Please try again.');
diff --git a/DependencyInjection/AvroCsvExtension.php b/DependencyInjection/AvroCsvExtension.php
index 0519cb1..3df9a1d 100644
--- a/DependencyInjection/AvroCsvExtension.php
+++ b/DependencyInjection/AvroCsvExtension.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index b196efd..b369c5c 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Doctrine/Importer.php b/Doctrine/Importer.php
index 70c60fe..7aeab90 100644
--- a/Doctrine/Importer.php
+++ b/Doctrine/Importer.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Event/AssociationFieldEvent.php b/Event/AssociationFieldEvent.php
new file mode 100644
index 0000000..cd3319e
--- /dev/null
+++ b/Event/AssociationFieldEvent.php
@@ -0,0 +1,101 @@
+<?php
+
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Avro\CsvBundle\Event;
+
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Row association event.
+ *
+ * @author Steffen Roßkamp <steffen.rosskamp@gimmickmedia.de>
+ */
+class AssociationFieldEvent extends Event
+{
+    protected $object;
+    protected $associationMapping;
+    protected $row;
+    protected $fields;
+    protected $headers;
+    protected $index;
+
+    /**
+     * @param object $object
+     * @param array  $associationMapping
+     * @param array  $row
+     * @param array  $fields
+     * @param array  $headers
+     * @param int    $index
+     */
+    public function __construct(object $object, array $associationMapping, array $row, array $fields, array $headers, int $index)
+    {
+        $this->object = $object;
+        $this->associationMapping = $associationMapping;
+        $this->row = $row;
+        $this->fields = $fields;
+        $this->headers = $headers;
+        $this->index = $index;
+    }
+
+    /**
+     * @return object
+     */
+    public function getObject(): object
+    {
+        return $this->object;
+    }
+
+    /**
+     * Get field association mapping.
+     *
+     * @return array
+     */
+    public function getAssociationMapping(): array
+    {
+        return $this->associationMapping;
+    }
+
+    /**
+     * Get field row.
+     *
+     * @return array
+     */
+    public function getRow(): array
+    {
+        return $this->row;
+    }
+
+    /**
+     * Get mapped fields.
+     *
+     * @return array
+     */
+    public function getFields(): array
+    {
+        return $this->fields;
+    }
+
+    /**
+     * Get CSV headers.
+     *
+     * @return array
+     */
+    public function getHeaders(): array
+    {
+        return $this->headers;
+    }
+
+    /**
+     * Get the current field index.
+     *
+     * @return int
+     */
+    public function getIndex(): int
+    {
+        return $this->index;
+    }
+}
diff --git a/Event/CustomFieldEvent.php b/Event/CustomFieldEvent.php
new file mode 100644
index 0000000..8c44847
--- /dev/null
+++ b/Event/CustomFieldEvent.php
@@ -0,0 +1,102 @@
+<?php
+
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Avro\CsvBundle\Event;
+
+use ReflectionClass;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Row association event.
+ *
+ * @author Steffen Roßkamp <steffen.rosskamp@gimmickmedia.de>
+ */
+class CustomFieldEvent extends Event
+{
+    protected $object;
+    protected $reflectionClass;
+    protected $row;
+    protected $fields;
+    protected $headers;
+    protected $index;
+
+    /**
+     * @param object          $object
+     * @param ReflectionClass $reflectionClass
+     * @param array           $row
+     * @param array           $fields
+     * @param array           $headers
+     * @param int             $index
+     */
+    public function __construct(object $object, ReflectionClass $reflectionClass, array $row, array $fields, array $headers, int $index)
+    {
+        $this->object = $object;
+        $this->reflectionClass = $reflectionClass;
+        $this->row = $row;
+        $this->fields = $fields;
+        $this->headers = $headers;
+        $this->index = $index;
+    }
+
+    /**
+     * @return object
+     */
+    public function getObject(): object
+    {
+        return $this->object;
+    }
+
+    /**
+     * Get object reflection class.
+     *
+     * @return ReflectionClass
+     */
+    public function getReflectionClass(): ReflectionClass
+    {
+        return $this->reflectionClass;
+    }
+
+    /**
+     * Get field row.
+     *
+     * @return array
+     */
+    public function getRow(): array
+    {
+        return $this->row;
+    }
+
+    /**
+     * Get mapped fields.
+     *
+     * @return array
+     */
+    public function getFields(): array
+    {
+        return $this->fields;
+    }
+
+    /**
+     * Get CSV headers.
+     *
+     * @return array
+     */
+    public function getHeaders(): array
+    {
+        return $this->headers;
+    }
+
+    /**
+     * Get the current field index.
+     *
+     * @return int
+     */
+    public function getIndex(): int
+    {
+        return $this->index;
+    }
+}
diff --git a/Event/ExportEvent.php b/Event/ExportEvent.php
index cb10fd1..ad4418e 100644
--- a/Event/ExportEvent.php
+++ b/Event/ExportEvent.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -33,7 +33,7 @@ public function __construct(ExporterInterface $exporter)
      *
      * @return ExporterInterface
      */
-    public function getExporter()
+    public function getExporter(): ExporterInterface
     {
         return $this->exporter;
     }
@@ -43,7 +43,7 @@ public function getExporter()
      *
      * @return QueryBuilder
      */
-    public function getQueryBuilder()
+    public function getQueryBuilder(): QueryBuilder
     {
         return $this->exporter->getQueryBuilder();
     }
diff --git a/Event/ExportedEvent.php b/Event/ExportedEvent.php
index 481a456..8ca7acf 100644
--- a/Event/ExportedEvent.php
+++ b/Event/ExportedEvent.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -21,7 +21,7 @@ class ExportedEvent extends Event
     /**
      * @param string $content Csv data
      */
-    public function __construct($content)
+    public function __construct(string $content)
     {
         $this->content = $content;
     }
@@ -31,7 +31,7 @@ public function __construct($content)
      *
      * @return string
      */
-    public function getContent()
+    public function getContent(): string
     {
         return $this->content;
     }
diff --git a/Event/RowAddedEvent.php b/Event/RowAddedEvent.php
index 9aea5d1..0735049 100644
--- a/Event/RowAddedEvent.php
+++ b/Event/RowAddedEvent.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -21,11 +21,11 @@ class RowAddedEvent extends Event
     protected $fields;
 
     /**
-     * @param \stdClass|null $object The new object being persisted
-     * @param array          $row    The row being imported
-     * @param array          $fields The mapped fields
+     * @param object $object The new object being persisted
+     * @param array  $row    The row being imported
+     * @param array  $fields The mapped fields
      */
-    public function __construct($object, array $row, array $fields)
+    public function __construct(object $object, array $row, array $fields)
     {
         $this->object = $object;
         $this->row = $row;
@@ -33,9 +33,9 @@ public function __construct($object, array $row, array $fields)
     }
 
     /**
-     * @param \stdClass|null $object
+     * @param object|null $object
      */
-    public function setObject($object)
+    public function setObject(?object $object): void
     {
         $this->object = $object;
     }
@@ -43,9 +43,9 @@ public function setObject($object)
     /**
      * Get the doctrine object.
      *
-     * @return \stdClass|null
+     * @return object|null
      */
-    public function getObject()
+    public function getObject(): ?object
     {
         return $this->object;
     }
@@ -55,7 +55,7 @@ public function getObject()
      *
      * @return array
      */
-    public function getRow()
+    public function getRow(): array
     {
         return $this->row;
     }
@@ -65,7 +65,7 @@ public function getRow()
      *
      * @return array
      */
-    public function getFields()
+    public function getFields(): array
     {
         return $this->fields;
     }
diff --git a/Event/RowErrorEvent.php b/Event/RowErrorEvent.php
index b59274c..e63fbed 100644
--- a/Event/RowErrorEvent.php
+++ b/Event/RowErrorEvent.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -34,7 +34,7 @@ public function __construct(array $row, array $fields)
      *
      * @return array
      */
-    public function getRow()
+    public function getRow(): array
     {
         return $this->row;
     }
@@ -44,7 +44,7 @@ public function getRow()
      *
      * @return array
      */
-    public function getFields()
+    public function getFields(): array
     {
         return $this->fields;
     }
diff --git a/Export/Doctrine/ORM/Exporter.php b/Export/Doctrine/ORM/Exporter.php
index ed02205..ab9f3d8 100644
--- a/Export/Doctrine/ORM/Exporter.php
+++ b/Export/Doctrine/ORM/Exporter.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Export/Exporter.php b/Export/Exporter.php
index e56f38b..d0a8d50 100644
--- a/Export/Exporter.php
+++ b/Export/Exporter.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Export/ExporterInterface.php b/Export/ExporterInterface.php
index 48f7acd..41babec 100644
--- a/Export/ExporterInterface.php
+++ b/Export/ExporterInterface.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
diff --git a/Form/Type/ImportFormType.php b/Form/Type/ImportFormType.php
index 7c28025..47eb4bb 100644
--- a/Form/Type/ImportFormType.php
+++ b/Form/Type/ImportFormType.php
@@ -1,5 +1,10 @@
 <?php
 
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Avro\CsvBundle\Form\Type;
 
 use Symfony\Component\Form\AbstractType;
diff --git a/Import/Importer.php b/Import/Importer.php
index 347fb19..7008a9c 100644
--- a/Import/Importer.php
+++ b/Import/Importer.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -9,6 +9,8 @@
 
 use Avro\CaseBundle\Util\CaseConverter;
 use Avro\CsvBundle\AvroCsvEvents;
+use Avro\CsvBundle\Event\AssociationFieldEvent;
+use Avro\CsvBundle\Event\CustomFieldEvent;
 use Avro\CsvBundle\Event\RowAddedEvent;
 use Avro\CsvBundle\Event\RowErrorEvent;
 use Avro\CsvBundle\Util\Reader;
@@ -93,7 +95,7 @@ public function __construct(Reader $reader, EventDispatcherInterface $dispatcher
      * @param string $delimiter    The csv's delimiter
      * @param string $headerFormat The header case format
      */
-    public function init($file, $class, $delimiter = ',', $headerFormat = 'title')
+    public function init($file, $class, $delimiter = ',', $headerFormat = 'title'): void
     {
         $this->reader->open($file, $delimiter);
         $this->class = $class;
@@ -110,11 +112,9 @@ public function init($file, $class, $delimiter = ',', $headerFormat = 'title')
      *
      * @param array $fields The fields to persist
      *
-     * @return true if successful
-     *
      * @throws MappingException
      */
-    public function import($fields)
+    public function import($fields): void
     {
         $fields = array_unique($this->caseConverter->toPascalCase($fields));
         while ($row = $this->reader->getRow()) {
@@ -131,8 +131,6 @@ public function import($fields)
         }
         // one last flush to make sure no persisted objects get left behind
         $this->objectManager->flush();
-
-        return true;
     }
 
     /**
@@ -157,35 +155,35 @@ public function toFormFieldName($input)
     }
 
     /**
-     * Generate a hash string suitable as form field name.
-     *
-     * @param string $input
+     * Get import count.
      *
-     * @return string
+     * @return int
      */
-    private function convertToFormFieldName($input)
+    public function getImportCount(): int
     {
-        return sha1($input);
+        return $this->importCount;
     }
 
     /**
-     * Get import count.
+     * Get import errors.
      *
      * @return int
      */
-    public function getImportCount()
+    public function getImportErrors(): int
     {
-        return $this->importCount;
+        return $this->importErrors;
     }
 
     /**
-     * Get import errors.
+     * Generate a hash string suitable as form field name.
      *
-     * @return int
+     * @param string $input
+     *
+     * @return string
      */
-    public function getImportErrors()
+    private function convertToFormFieldName($input): string
     {
-        return $this->importErrors;
+        return sha1($input);
     }
 
     /**
@@ -195,63 +193,25 @@ public function getImportErrors()
      * @param array $fields   An array of the fields to import
      * @param bool  $andFlush Flush the ObjectManager
      *
-     * @return bool
-     *
      * @throws MappingException
+     *
+     * @return bool
      */
-    private function addRow($row, $fields, $andFlush = true)
+    private function addRow($row, $fields, $andFlush = true): bool
     {
         // Create new entity
         $entity = new $this->class();
-        if (in_array('Id', $fields)) {
-            $key = array_search('Id', $fields);
-            if ($this->metadata->hasField('legacyId')) {
-                $entity->setLegacyId($row[$key]);
-            }
-            unset($fields[$key]);
-        }
-        // loop through fields and set to row value
+        // Loop through fields and set to row value
         foreach ($fields as $k => $v) {
             if ($this->metadata->hasField(lcfirst($v))) {
-                $entity->{'set'.$fields[$k]}($row[$k]);
+                $entity->{'set'.$v}($row[$k]);
             } elseif ($this->metadata->hasAssociation(lcfirst($v))) {
-                $association = $this->metadata->getAssociationMapping(lcfirst($v));
-                switch ($association['type']) {
-                    case '1': // oneToOne
-                        //Todo:
-                        break;
-                    case '2': // manyToOne
-                        break;
-                        // still needs work
-                        $joinColumnId = $association['joinColumns'][0]['name'];
-                        $legacyId = $row[array_search($this->caseConverter->toCamelCase($joinColumnId), $this->headers)];
-                        if ($legacyId) {
-                            try {
-                                $criteria = ['legacyId' => $legacyId];
-                                if ($this->useOwner) {
-                                    $criteria['owner'] = $this->owner->getId();
-                                }
-
-                                $associationClass = new \ReflectionClass($association['targetEntity']);
-                                if ($associationClass->hasProperty('legacyId')) {
-                                    $relation = $this->objectManager->getRepository($association['targetEntity'])->findOneBy($criteria);
-                                    if ($relation) {
-                                        $entity->{'set'.ucfirst($association['fieldName'])}($relation);
-                                    }
-                                }
-                            } catch (\Exception $e) {
-                                // legacyId does not exist
-                                // fail silently
-                            }
-                        }
-                        break;
-                    case '4': // oneToMany
-                        //TODO:
-                        break;
-                    case '8': // manyToMany
-                        //TODO:
-                        break;
-                }
+                // Let implementors handle associations to allow complex cases
+                $event = new AssociationFieldEvent($entity, $this->metadata->getAssociationMapping(lcfirst($v)), $row, $fields, $this->headers, $k);
+                $this->dispatcher->dispatch(AvroCsvEvents::ASSOCIATION_FIELD, $event);
+            } elseif ($this->metadata->getReflectionClass()->hasProperty(lcfirst($v))) {
+                $event = new CustomFieldEvent($entity, $this->metadata->getReflectionClass(), $row, $fields, $this->headers, $k);
+                $this->dispatcher->dispatch(AvroCsvEvents::CUSTOM_FIELD, $event);
             }
         }
         // Allow RowAddedEvent listeners to nullify objects (i.e. when invalid)
diff --git a/Import/ImporterInterface.php b/Import/ImporterInterface.php
index 15986f4..3b512bd 100644
--- a/Import/ImporterInterface.php
+++ b/Import/ImporterInterface.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -24,18 +24,16 @@ interface ImporterInterface
      * @param string $delimiter    The csv's delimiter
      * @param string $headerFormat The header case format
      */
-    public function init($file, $class, $delimiter = ',', $headerFormat = 'title');
+    public function init($file, $class, $delimiter = ',', $headerFormat = 'title'): void;
 
     /**
      * Import the csv and persist to database.
      *
      * @param array $fields The fields to persist
      *
-     * @return true if successful
-     *
      * @throws MappingException
      */
-    public function import($fields);
+    public function import($fields): void;
 
     /**
      * Converts a string to a format suitable as form name.
@@ -51,12 +49,12 @@ public function toFormFieldName($input);
      *
      * @return int
      */
-    public function getImportCount();
+    public function getImportCount(): int;
 
     /**
      * Get import errors.
      *
      * @return int
      */
-    public function getImportErrors();
+    public function getImportErrors(): int;
 }
diff --git a/README.md b/README.md
index aab72c3..79d6b99 100644
--- a/README.md
+++ b/README.md
@@ -127,6 +127,72 @@ Views
 The bundle comes with some basic twitter bootstrap views that you can 
 override by extending the bundle.
 
+Association mapping
+-------------------
+
+An event is fired when importing an association field to allow implementing your
+own logic fitting
+ 
+Just create a custom listener in your app that listens for the ``AvroCsvEvents::ASSOCIATION_FIELD`` event.
+
+A simple implementation getting an associated entity by name could look like:
+
+```php
+namespace App\EventListener;
+
+use Avro\CsvBundle\AvroCsvEvents;
+use Avro\CsvBundle\Event\AssociationFieldEvent;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Mapping\ClassMetadataInfo;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Csv import listener
+ */
+class ImportListener implements EventSubscriberInterface
+{
+    private $em;
+
+    /**
+     * @param EntityManagerInterface   $em      The entity manager
+     */
+    public function __construct(EntityManagerInterface $em)
+    {
+        $this->em = $em;
+    }
+    
+    public static function getSubscribedEvents()
+    {
+        return [
+            AvroCsvEvents::ASSOCIATION_FIELD => 'importAssociation',
+        ];
+    }
+
+    /**
+     * Set the objects createdBy field
+     *
+     * @param AssociationFieldEvent $event
+     */
+    public function importAssociation(AssociationFieldEvent $event)
+    {
+        $association = $event->getAssociationMapping();
+        switch ($association['type']) {
+            case ClassMetadataInfo::ONE_TO_ONE:
+            case ClassMetadataInfo::MANY_TO_ONE:
+                $relation = $this->em->getRepository($association['targetEntity'])->findOneBy(
+                    [
+                        'name' => $event->getRow()[$event->getIndex()],
+                    ]
+                );
+                if ($relation) {
+                    $event->getObject()->{'set'.ucfirst($association['fieldName'])}($relation);
+                }
+                break;
+        }
+    }
+}
+```
+
 Customizing each row
 --------------------
 
@@ -247,7 +313,6 @@ Register your controller or use your already setup autowiring
 To Do:
 ------
 
-- Allow association mapping 
 - Finish mongodb support
 
 Acknowledgements
diff --git a/Tests/Doctrine/ImporterTest.php b/Tests/Doctrine/ImporterTest.php
index 2ee408c..ac8fcf5 100644
--- a/Tests/Doctrine/ImporterTest.php
+++ b/Tests/Doctrine/ImporterTest.php
@@ -1,12 +1,21 @@
 <?php
 
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Avro\CsvBundle\Tests\Doctrine;
 
 use Avro\CaseBundle\Util\CaseConverter;
 use Avro\CsvBundle\Doctrine\Importer;
+use Avro\CsvBundle\Tests\TestEntity;
 use Avro\CsvBundle\Util\Reader;
+use Doctrine\Common\Persistence\ObjectManager;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
-class ImporterTest extends \PHPUnit_Framework_TestCase
+class ImporterTest extends TestCase
 {
     protected $fieldRetriever;
     protected $class;
@@ -19,27 +28,13 @@ public function setUp()
     {
         $caseConverter = new CaseConverter();
         $reader = new Reader();
-        $metadata = $this->createMock('Doctrine\Common\Persistence\Mapping\ClassMetadata');
-        $metadata
-            ->expects($this->any())
-            ->method('hasField')
-            ->willReturn(true);
-        $metadataFactory = $this->createMock('Doctrine\Common\Persistence\Mapping\ClassMetadataFactory');
-        $metadataFactory
-            ->expects($this->any())
-            ->method('getMetadataFor')
-            ->willReturn($metadata);
-        $objectManager = $this->createMock('Doctrine\Common\Persistence\ObjectManager');
-        $objectManager
-            ->expects($this->any())
-            ->method('getMetadataFactory')
-            ->willReturn($metadataFactory);
-        $dispatcher = $this->createMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
-
-        $class = 'Avro\CsvBundle\Tests\TestEntity';
+        $objectManager = $this->createMock(ObjectManager::class);
+        $dispatcher = $this->createMock(EventDispatcherInterface::class);
+
+        $class = TestEntity::class;
 
         $this->importer = new Importer($reader, $dispatcher, $caseConverter, $objectManager, 5);
-        $this->importer->init(__DIR__.'/../import.csv', $class, ',', 'title');
+        $this->importer->init(__DIR__.'/../import.csv', $class);
     }
 
     /**
diff --git a/Tests/Export/Doctrine/ORM/ExporterTest.php b/Tests/Export/Doctrine/ORM/ExporterTest.php
index fe2f93b..f81509e 100644
--- a/Tests/Export/Doctrine/ORM/ExporterTest.php
+++ b/Tests/Export/Doctrine/ORM/ExporterTest.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -8,12 +8,16 @@
 namespace Avro\CsvBundle\Tests\Export\Doctrine\ORM;
 
 use Avro\CsvBundle\Export\Doctrine\ORM\Exporter;
+use Avro\CsvBundle\Tests\TestEntity;
+use Doctrine\ORM\AbstractQuery;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\QueryBuilder;
+use PHPUnit\Framework\TestCase;
 
 /**
  * Test exporter class.
  */
-class ExporterTest extends \PHPUnit_Framework_TestCase
+class ExporterTest extends TestCase
 {
     /**
      * @var Exporter
@@ -22,34 +26,31 @@ class ExporterTest extends \PHPUnit_Framework_TestCase
 
     public function setUp()
     {
-        $query = $this->getMockBuilder('Doctrine\ORM\AbstractQuery')
-            ->disableOriginalConstructor()
-            ->setMethods(['iterate', 'HYDRATE_ARRAY', 'getSQL', '_doExecute'])
-            ->getMock();
-        $query->expects($this->any())
+        $query = $this->getMockForAbstractClass(AbstractQuery::class, [], '', false, true, true, ['iterate', 'HYDRATE_ARRAY', 'getSQL', '_doExecute']);
+        $query
             ->method('iterate')
             ->willReturn([0 => [0 => ['row 1' => 'val\'1', 'row 2' => 'val,2', 'row 3' => 'val"3']]]);
-        $queryBuilder = $this->getMockBuilder('Doctrine\ORM\QueryBuilder')
+        $queryBuilder = $this->getMockBuilder(QueryBuilder::class)
             ->disableOriginalConstructor()
             ->setMethods(['select', 'from', 'getQuery'])
             ->getMock();
-        $queryBuilder->expects($this->any())
+        $queryBuilder
             ->method('select')
             ->willReturn($queryBuilder);
-        $queryBuilder->expects($this->any())
+        $queryBuilder
             ->method('from')
             ->willReturn($queryBuilder);
-        $queryBuilder->expects($this->any())
+        $queryBuilder
             ->method('from')
             ->willReturn($queryBuilder);
-        $queryBuilder->expects($this->any())
+        $queryBuilder
             ->method('getQuery')
             ->willReturn($query);
-        $entityManager = $this->getMockBuilder('Doctrine\ORM\EntityManager')
+        $entityManager = $this->getMockBuilder(EntityManager::class)
             ->disableOriginalConstructor()
             ->setMethods(['createQueryBuilder'])
             ->getMock();
-        $entityManager->expects($this->any())
+        $entityManager
             ->method('createQueryBuilder')
             ->willReturn($queryBuilder);
 
@@ -61,8 +62,8 @@ public function setUp()
      */
     public function testInit()
     {
-        $this->exporter->init('Avro\CsvBundle\Tests\TestEntity');
-        $this->assertTrue($this->exporter->getQueryBuilder() instanceof QueryBuilder);
+        $this->exporter->init(TestEntity::class);
+        $this->assertInstanceOf(QueryBuilder::class, $this->exporter->getQueryBuilder());
     }
 
     /**
@@ -71,7 +72,7 @@ public function testInit()
     public function testArrayToCsv()
     {
         $this->assertEquals(
-            '"val\'1","val,2","val""3"' . "\n",
+            '"val\'1","val,2","val""3"'."\n",
             $this->exporter->arrayToCsv(['val\'1', 'val,2', 'val"3'])
         );
     }
@@ -86,7 +87,7 @@ public function testGetContent()
         $expected .= '"val\'1","val,2","val""3"';
         $expected .= "\n";
 
-        $this->exporter->init('Avro\CsvBundle\Tests\TestEntity');
+        $this->exporter->init(TestEntity::class);
         $this->assertEquals(
             $expected,
             $this->exporter->getContent()
diff --git a/Tests/Import/ImporterTest.php b/Tests/Import/ImporterTest.php
index d38afdb..12e80f4 100644
--- a/Tests/Import/ImporterTest.php
+++ b/Tests/Import/ImporterTest.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -9,12 +9,17 @@
 
 use Avro\CaseBundle\Util\CaseConverter;
 use Avro\CsvBundle\Import\Importer;
+use Avro\CsvBundle\Tests\TestEntity;
 use Avro\CsvBundle\Util\Reader;
+use Doctrine\Common\Persistence\ObjectManager;
+use Doctrine\ORM\Mapping\ClassMetadataInfo;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 /**
  * Test importer class.
  */
-class ImporterTest extends \PHPUnit_Framework_TestCase
+class ImporterTest extends TestCase
 {
     /**
      * @var string[]
@@ -31,31 +36,40 @@ class ImporterTest extends \PHPUnit_Framework_TestCase
     public function setUp()
     {
         $fields = ['id', 'field1', 'field2'];
-        $this->fields = $fields;
+        $assocs = ['assoc'];
+        $customs = ['assoc'];
+        $this->fields = array_merge($fields, $assocs, $customs);
         $caseConverter = new CaseConverter();
         $reader = new Reader();
-        $metadata = $this->getMockForAbstractClass('Doctrine\Common\Persistence\Mapping\ClassMetadata', ['hasField']);
-        $metadata->expects($this->any())
+        $metadata = $this->createMock(ClassMetadataInfo::class);
+        $metadata
             ->method('hasField')
-            ->will(
-                $this->returnCallback(
-                    function ($value) use ($fields) {
-                        return in_array($value, $fields);
-                    }
-                )
+            ->willReturnCallback(
+                static function ($value) use ($fields) {
+                    return in_array($value, $fields, true);
+                }
+            );
+        $metadata
+            ->method('hasAssociation')
+            ->willReturnCallback(
+                static function ($value) use ($assocs) {
+                    return in_array($value, $assocs, true);
+                }
             );
-        $objectManager = $this->createMock('Doctrine\Common\Persistence\ObjectManager');
-        $objectManager->expects($this->any())
+        $metadata
+            ->method('getAssociationMapping')
+            ->willReturn([]);
+        $objectManager = $this->createMock(ObjectManager::class);
+        $objectManager
             ->method('getClassMetadata')
             ->willReturn($metadata);
-        $dispatcher = $this->createMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
-        $dispatcher->expects($this->any())
+        $dispatcher = $this->createMock(EventDispatcherInterface::class);
+        $dispatcher
             ->method('dispatch')
             ->willReturn('true');
 
         $this->importer = new Importer($reader, $dispatcher, $caseConverter, $objectManager, 5);
-
-        $this->importer->init(__DIR__.'/../import.csv', 'Avro\CsvBundle\Tests\TestEntity', ',', 'title');
+        $this->importer->init(__DIR__.'/../import.csv', TestEntity::class);
     }
 
     /**
@@ -63,11 +77,7 @@ function ($value) use ($fields) {
      */
     public function testImport()
     {
-        $this->assertEquals(
-            true,
-            $this->importer->import($this->fields)
-        );
-
+        $this->importer->import($this->fields);
         $this->assertEquals(
             3,
             $this->importer->getImportCount()
diff --git a/Tests/TestEntity.php b/Tests/TestEntity.php
index 7a92c6f..6d2da0c 100644
--- a/Tests/TestEntity.php
+++ b/Tests/TestEntity.php
@@ -1,5 +1,10 @@
 <?php
 
+/*
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Avro\CsvBundle\Tests;
 
 class TestEntity
@@ -10,6 +15,10 @@ class TestEntity
 
     protected $field2;
 
+    protected $assoc;
+
+    protected $custom;
+
     public function getId()
     {
         return $this->id;
@@ -39,4 +48,24 @@ public function setField2($field2)
     {
         $this->field2 = $field2;
     }
+
+    public function getAssoc()
+    {
+        return $this->assoc;
+    }
+
+    public function setAssoc($assoc): void
+    {
+        $this->assoc = $assoc;
+    }
+
+    public function getCustom()
+    {
+        return $this->custom;
+    }
+
+    public function setCustom($custom): void
+    {
+        $this->custom = $custom;
+    }
 }
diff --git a/Tests/Util/FieldRetrieverTest.php b/Tests/Util/FieldRetrieverTest.php
index 30bf966..a7b407c 100644
--- a/Tests/Util/FieldRetrieverTest.php
+++ b/Tests/Util/FieldRetrieverTest.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -8,10 +8,12 @@
 namespace Avro\CsvBundle\Tests\Util;
 
 use Avro\CaseBundle\Util\CaseConverter;
+use Avro\CsvBundle\Tests\TestEntity;
 use Avro\CsvBundle\Util\FieldRetriever;
 use Doctrine\Common\Annotations\AnnotationReader;
+use PHPUnit\Framework\TestCase;
 
-class FieldRetrieverTest extends \PHPUnit_Framework_TestCase
+class FieldRetrieverTest extends TestCase
 {
     /**
      * @var FieldRetriever
@@ -27,7 +29,7 @@ public function setUp()
         $annotationReader = new AnnotationReader();
         $caseConverter = new CaseConverter();
         $this->fieldRetriever = new FieldRetriever($annotationReader, $caseConverter);
-        $this->class = 'Avro\CsvBundle\Tests\TestEntity';
+        $this->class = TestEntity::class;
     }
 
     public function testGetFields()
@@ -39,6 +41,8 @@ public function testGetFields()
                 '1' => 'Id',
                 '2' => 'Field1',
                 '3' => 'Field2',
+                '4' => 'Assoc',
+                '5' => 'Custom',
             ]
         );
     }
@@ -52,6 +56,8 @@ public function testGetFieldsAsCamelCase()
                 '1' => 'id',
                 '2' => 'field1',
                 '3' => 'field2',
+                '4' => 'assoc',
+                '5' => 'custom',
             ]
         );
     }
@@ -65,6 +71,8 @@ public function testGetFieldsAndCopyKeys()
                 'id' => 'id',
                 'field1' => 'field1',
                 'field2' => 'field2',
+                'assoc' => 'assoc',
+                'custom' => 'custom',
             ]
         );
     }
diff --git a/Tests/Util/ReaderTest.php b/Tests/Util/ReaderTest.php
index 86d4582..f097e13 100644
--- a/Tests/Util/ReaderTest.php
+++ b/Tests/Util/ReaderTest.php
@@ -1,6 +1,6 @@
 <?php
 
-/**
+/*
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -8,8 +8,9 @@
 namespace Avro\CsvBundle\Tests\Util;
 
 use Avro\CsvBundle\Util\Reader;
+use PHPUnit\Framework\TestCase;
 
-class ReaderTest extends \PHPUnit_Framework_TestCase
+class ReaderTest extends TestCase
 {
     /**
      * @var Reader
diff --git a/composer.json b/composer.json
index 6624d26..1d8ec39 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         }
     },
     "require": {
-        "php": "^7.1.3",
+        "php": "^7.2.0",
         "ext-json": "*",
         "avro/case-bundle": "*"
     },