Yii's ORM management of relations

Hello.

I am a new User to Yii and I would like to know about relation management in Yii`s ORM.

Let me give a simple example:

I have 2 objects

- Document


	+ id int PK


- DocumentContent


	+ id int PK


	+ document_id int FK Document(id)





And I would like change the relation





    $documentContent = DocumentContent::model()->findByPk(1);


    var_dump($documentContent->document_id);    // output: 2 -> OK


    var_dump($documentContent->document->id);   // output: 2 -> OK





    $document = Document::model()->findByPk(3);


	


    $documentContent->document = $document;     // update object setter


    $documentContent->save();


    var_dump($documentContent->document_id);    // output: 2 -> NOT OK expecting 3


    var_dump($documentContent->document->id);   // output: 3 -> OK


	


    $documentContent->document_id = 4;          // update relation setter


    $documentContent->save();


    var_dump($documentContent->document_id);    // output: 4 -> OK


    var_dump($documentContent->document->id);   // output: 3 -> NOT OK expecting 4


    $documentContent->save();


	


    $documentContent->refresh();


    var_dump($documentContent->document_id);    // output: 4 -> OK


    var_dump($documentContent->document->id);   // output: 4 -> OK





Yii's ORM does not refresh object automatically ( after a setter call or a save). Other ORM like Propel does and I think it is a good idea in order to preserve data integrity. 

Is it planned to integrate to Yii? Is it an existing behavior? Am I doing something wrong?

Thanks in advance.

Ps: sorry for my english

Ps2: I have made a quick search and I don’t found similar post, So if existing, I apologize.