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manual/new/docs/en/working-with-objects.txt

@@ -2,7 +2,7 @@
 ++ Many-to-Many relations
 +++ Creating a new link
 Lets say we have two classes User and Group which are linked trhough a GroupUser association class. When working with transient (new) records the fastest way for adding a User and couple of Groups for it is:
-<code type='php'>
+<code type="php">
 $user = new User();
 $user->name = 'Some User';
 $user->Group[0]->name = 'Some Group';
@@ -11,7 +11,7 @@ $user->save();
 </code>
 
 However in real world scenarious you often already have existing groups, where you want to add a given user. The most efficient way of doing this is:
-<code type='php'>
+<code type="php">
 $gu = new GroupUser();
 $gu->user_id = $userId;
 $gu->group_id = $groupId;
@@ -22,16 +22,18 @@ $gu->save();
 
 While the obvious and convinient way of deleting a link between User and Group would be the following, you still should *NOT* do this:
 
-<code type='php'>
+<code type="php">
 $user = $conn->getTable('User')->find(5);
 $user->GroupUser
      ->remove(0)
      ->remove(1);
 </code>
 
+This is due to a fact that $user->GroupUser loads all group links for given user. This can time-consuming task if user belongs to many groups. Even if the user belongs to few groups this will still execute an unnecessary SELECT statement.
+
 The right way to delete links between many-to-many associated records is by using the DQL DELETE statement. Convenient and recommended way of using DQL DELETE is trhough the Query API.
 
-<code type='php'>
+<code type="php">
 $deleted = Doctrine_Query::create()
            ->delete()
            ->from('GroupUser')