diff --git a/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php b/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
index 3d506d0..c73a5c1 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityDatabaseStorage.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Entity;
 
+use Drupal\Component\Utility\String;
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Entity\Query\QueryInterface;
@@ -825,16 +826,29 @@ protected function mapToStorageRecord(ContentEntityInterface $entity, $table_nam
     $record = new \stdClass();
     $table_mapping = $this->getTableMapping();
     foreach ($table_mapping->getFieldNames($table_name) as $field_name) {
+
+      if (empty($this->storageDefinitions[$field_name])) {
+        throw new EntityStorageException(String::format('Table mapping contains invalid field %field.', array('%field' => $field_name)));
+      }
+      $definition = $this->storageDefinitions[$field_name];
       $columns = $table_mapping->getColumnNames($field_name);
-      if (!empty($this->storageDefinitions[$field_name])) {
-        $definition = $this->storageDefinitions[$field_name];
-        foreach ($columns as $column_name => $schema_name) {
+
+      foreach ($columns as $column_name => $schema_name) {
+        // If there is no main property and only a single column, get all
+        // properties from the first field item and assume that they will be
+        // stored serialized.
+        // @todo Give field types more control over this behavior in
+        //   https://drupal.org/node/2232427.
+        if (!$definition->getMainPropertyName() && count($columns) == 1) {
+          $value = $entity->$field_name->first()->getValue();
+        }
+        else {
           $value = isset($entity->$field_name->$column_name) ? $entity->$field_name->$column_name : NULL;
-          if (!empty($definition->getSchema()['columns'][$column_name]['serialize'])) {
-            $value = serialize($value);
-          }
-          $record->$schema_name = drupal_schema_get_field_value($definition->getSchema()['columns'][$column_name], $value);
         }
+        if (!empty($definition->getSchema()['columns'][$column_name]['serialize'])) {
+          $value = serialize($value);
+        }
+        $record->$schema_name = drupal_schema_get_field_value($definition->getSchema()['columns'][$column_name], $value);
       }
     }