link in a CGridView

hello,

i'd like to insert a link in a CGridView in order to link my posts to their authors.

i tried with this code, but had no success:

<?php $this->widget('zii.widgets.grid.CGridView', array(
	'id'=>'posts-grid',
	'dataProvider'=>$model->search(),
	'filter'=>$model,
	'columns'=>array(
		//'id_posts',
		array(
                    'class'=>'CLinkColumn',
                    'label'=>'id_post_author',
                    'url'=>'users/view&id='.$model->id_post_author,
                    'header'=>'Author'
                    ),
		'date',
		'content',
		'title',
		'excerpt',
		/*
		'status',
		'url',
		'id_cliente',
		'immagine_fissa',
		'immagine',
		*/
		array(
			'class'=>'CButtonColumn',
		),
	),
)); ?>

It looks like $model->id_post_author is always empty...

plus, but minor problem: this column can't be searched... why?

thanks a lot