diff --git a/entityreference.install b/entityreference.install
index caae34e..d75fca9 100644
--- a/entityreference.install
+++ b/entityreference.install
@@ -13,15 +13,9 @@ function entityreference_field_schema($field) {
           'unsigned' => TRUE,
           'not null' => FALSE,
         ),
-        'target_type' => array(
-          'description' => 'The type of the target entity',
-          'type' => 'varchar',
-          'length' => 255,
-          'not null' => TRUE,
-        ),
       ),
       'indexes' => array(
-        'target_entity' => array('target_type', 'target_id'),
+        'target_id' => array('target_id'),
       ),
       'foreign keys' => array(),
     );
@@ -73,3 +67,24 @@ function entityreference_update_7000() {
     }
   }
 }
+
+/**
+ * Drop "target_type" from the field schema.
+ */
+function entityreference_update_7001() {
+  foreach (field_info_fields() as $field_name => $field) {
+    if ($field['type'] != 'entityreference') {
+      continue;
+    }
+    $table_name = _field_sql_storage_tablename($field);
+    $revision_name = _field_sql_storage_revision_tablename($field);
+
+    db_drop_field($table_name, $field_name . '_target_type');
+    db_drop_index($table_name, $field_name . '_target_entity');
+    db_add_index($table_name, $field_name . '_target_id', array($field_name . '_target_id'));
+
+    db_drop_field($revision_name, $field_name . '_target_type');
+    db_drop_index($revision_name, $field_name . '_target_entity');
+    db_add_index($revision_name, $field_name . '_target_id', array($field_name . '_target_id'));
+  }
+}
diff --git a/entityreference.module b/entityreference.module
index 2327e9b..0db902b 100644
--- a/entityreference.module
+++ b/entityreference.module
@@ -114,17 +114,6 @@ function entityreference_field_validate($entity_type, $entity, $field, $instance
 }
 
 /**
- * Implements hook_field_presave().
- *
- * Adds the target type to the field data structure when saving.
- */
-function entityreference_field_presave($entity_type, $entity, $field, $instance, $langcode, &$items) {
-  foreach ($items as $delta => $item) {
-    $items[$delta]['target_type'] = $field['settings']['target_type'];
-  }
-}
-
-/**
  * Implements hook_field_settings_form().
  */
 function entityreference_field_settings_form($field, $instance, $has_data) {