Saving Many-to-Many Relationships with TokenInput

Saving Many-to-Many Relationships with TokenInput

Help me, Oh Mighty Hive Mind. You're my only hope.
I have been working on a small app for work that I'm building around a
database (go figure). While I have managed to save relationship data more
manually by iterating through the data, creating a new model for each, and
then saving that information, I know there must be a cleaner way than
this:
foreach($keys as $k) {
//Build the model to associate with keyword $k
$facts_keyword=new FactsKeyword;
$facts_keyword['fact_id']=$model->id;
$facts_keyword['keyword_id']=$k;
if(!$facts_keyword->save()) //Check for errors on saving
echo "FAILURE TO SAVE FACTS_KEYWORDS";
}
To make this work, I have made a model for the reference table between the
tables facts and keywords. The reference table simply has two columns
facts_id and keywords_id. I am using the TokenInput plugin for Yii to
input the keywords that are associated with a given fact. The relevant
view code is here:
<div id="keywords" class="row">
<?php echo $form->labelEx($keyword,'keywords'); ?>
<?php $this->widget('ext.tokeninput.TokenInput', array(
'model'=>$keyword,
'attribute'=>'name',
'url'=>array('keyword/searchKeys'),
'options' => array(
'allowCreation'=>false,
'preventDuplicates'=>true,
'resultsFormatter'=>'js:function(item){ return "<li><p>" +
item.name + "</p></li>" }',
'prePopulate'=>$key,
'theme'=>'facebook',
'minChars'=>2,
)
)); ?>
<?php echo $form->error($keyword,'name'); ?>
</div>
The relationship from the fact model looks like this: 'sources' =>
array(self::MANY_MANY, 'MinorSource', 'sources_facts(fact_id,
minorSource_id)'
How can I save the information from the my view in a cleaner way? I have
tried to change 'model'=>$keyword to 'model'=>$fact and changing
'attribute'=>'name' to 'attribute'=>'sources' That gives this error:
trim() expects parameter 1 to be string, array given What am I doing
wrong?