diff --git modules/field/modules/field_sql_storage/field_sql_storage.module modules/field/modules/field_sql_storage/field_sql_storage.module
index 9f85a10..522d816 100644
--- modules/field/modules/field_sql_storage/field_sql_storage.module
+++ modules/field/modules/field_sql_storage/field_sql_storage.module
@@ -677,9 +677,13 @@ function field_sql_storage_field_storage_purge_field($field) {
  */
 function field_sql_storage_field_storage_details($field) {
   $details = array();
+  $columns = array();
+  $field += array(
+    'columns' => array(),
+  );
 
   // Add field columns.
-  foreach ((array) $field['columns'] as $column_name => $attributes) {
+  foreach ($field['columns'] as $column_name => $attributes) {
     $real_name = _field_sql_storage_columnname($field['field_name'], $column_name);
     $columns[$column_name] = $real_name;
   }