diff --git a/.travis.yml b/.travis.yml
index 4b5923f..e11281f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,9 +11,6 @@ env:
 services:
   - memcached
 
-install:
-  - sudo apt-get install -y --force-yes apache2 libapache2-mod-php5 php5-curl php5-intl
-
 before_script:
   - phpenv config-add custom.ini
   - composer self-update
diff --git a/src/Slick/Orm/Entity.php b/src/Slick/Orm/Entity.php
index 69c6442..af64778 100644
--- a/src/Slick/Orm/Entity.php
+++ b/src/Slick/Orm/Entity.php
@@ -12,6 +12,7 @@
 
 namespace Slick\Orm;
 
+use Slick\Database\RecordList;
 use Slick\Database\Sql;
 use Slick\Orm\Events\Delete;
 use Slick\Orm\Events\Save;
@@ -113,6 +114,9 @@ public static function get($id)
     public static function find($fields = '*')
     {
         $entity = new static();
+        if ($fields == '*') {
+            $fields = $entity->getTableName() .'.*';
+        }
         Entity\Manager::getInstance()->get($entity)->refreshRelations();
         $select = new \Slick\Orm\Sql\Select($entity, $fields);
         return $select;
@@ -259,4 +263,69 @@ protected function _setData(array $data)
 
         return $data;
     }
+
+    /**
+     * Recursively returns this entity as an array. Used in json and
+     * serialization processes.
+     *
+     * @return array
+     */
+    public function asArray()
+    {
+        $data = [];
+        $columns = Manager::getInstance()->get($this)->getColumns();
+        foreach(array_keys($columns) as $field) {
+            $data[trim($field, '_')] = $this->$field;
+        }
+        $relations = Manager::getInstance()->get($this)->getRelations();
+        foreach(array_keys($relations) as $field) {
+            if ($this->$field instanceof Entity) {
+                $data[trim($field, '_')] = $this->$field->asArray();
+            } elseif ($this->$field instanceof RecordList) {
+                $values = [];
+                foreach ($this->$field as $entity) {
+                    $values[] = $entity->asArray();
+                }
+                $data[trim($field, '_')] = $values;
+            } else {
+                $data[trim($field, '_')] = $this->$field;
+            }
+        }
+        return $data;
+
+    }
+
+    /**
+     * Serializes this entity
+     *
+     * @return string
+     */
+    public function serialize()
+    {
+        $data = $this->asArray();
+        $serialize = serialize($data);
+        return $serialize;
+    }
+
+    /**
+     * Unserialize callback handle
+     *
+     * @param string $data
+     * @return self
+     */
+    public function unserialize($data)
+    {
+        $this->_createObject(unserialize($data));
+        return $this;
+    }
+
+    /**
+     * Returns this entity in JSON format
+     *
+     * @return string
+     */
+    public function asJason()
+    {
+        return json_encode($this->asArray());
+    }
 }
diff --git a/src/Slick/Orm/Relation/AbstractRelation.php b/src/Slick/Orm/Relation/AbstractRelation.php
index b327c3a..40c83c5 100644
--- a/src/Slick/Orm/Relation/AbstractRelation.php
+++ b/src/Slick/Orm/Relation/AbstractRelation.php
@@ -17,6 +17,7 @@
 use Slick\Di\Container;
 use Slick\Di\Definition;
 use Slick\Di\ContainerBuilder;
+use Slick\Orm\Exception\InvalidArgumentException;
 use Slick\Orm\RelationInterface;
 use Slick\Common\Inspector\Annotation;
 
@@ -119,7 +120,13 @@ public function getRelatedEntity()
      */
     public function setRelatedEntity($entity)
     {
+        if (!class_exists($entity)) {
+            throw new InvalidArgumentException(
+                "The entity class '{$entity}' does not exists."
+            );
+        }
         $this->_relatedEntity = $entity;
+        return $this;
     }
 
     /**
@@ -234,10 +241,20 @@ public static function create(
         $parameters = $annotation->getParameters();
         unset ($parameters['_raw']);
 
+        $related = $annotation->getValue();
+        if (!class_exists($related)) {
+            $parentClass = $entity->getClassName();
+            throw new InvalidArgumentException(
+                "Unknown class defined in {$parentClass}::_{$property}. ".
+                "Class {$related} does not exists."
+            );
+        }
+
         /** @var BelongsTo $relation */
         $relation = new static($parameters);
         $relation->setEntity($entity)->setPropertyName($property);
-        $relation->setRelatedEntity($annotation->getValue());
+
+        $relation->setRelatedEntity($related);
         return $relation;
     }
 }
diff --git a/src/Slick/Orm/Relation/AbstractSingleRelation.php b/src/Slick/Orm/Relation/AbstractSingleRelation.php
index ca8ee9a..9e8ac38 100644
--- a/src/Slick/Orm/Relation/AbstractSingleRelation.php
+++ b/src/Slick/Orm/Relation/AbstractSingleRelation.php
@@ -103,27 +103,29 @@ public function afterSelect(Select $event)
         $relatedTable = $related->getEntity()->getTableName();
         $class = $related->getEntity()->getClassName();
         foreach ($data as $key => $row) {
+
             $pmk =  $this->getEntity()->getPrimaryKey();
             if (isset($row[$pmk]) && is_array($row[$pmk])) {
                 $data[$key][$pmk] = reset($row[$pmk]);
             }
             $options = [];
-            foreach ($row as $column => $value) {
-                if (preg_match('/'.$relatedTable.'_(.*)/i', $column)) {
-                    unset($data[$key][$column]);
-                    $name = str_replace($relatedTable.'_', '', $column);
-                    $options[$name] = $value;
+            if (is_array($row)) {
+                foreach ($row as $column => $value) {
+                    if (preg_match('/' . $relatedTable . '_(.*)/i', $column)) {
+                        unset($data[$key][$column]);
+                        $name = str_replace($relatedTable . '_', '', $column);
+                        $options[$name] = $value;
+                    }
                 }
             }
-
             $data[$key][$this->getPropertyName()] = new $class($options);
         }
 
         if ($multiple) {
             $event->data = $data;
         } else {
-
-        }$event->data = reset($data);
+            $event->data = reset($data);
+        }
     }
 
 }