Working with HABTM associations

I’ve done some functions for working with HABTM associations.
For example:
You’ve the model Post and the model Tag. Post HABTM Tag.
You want to add the Tag with id 12 to the Post with id 3. Then you can do it easy with
$this->Post->addAssoc(3,’Tag’,12);

Now you want to delete the association between the Post 3 and the Tag 15? $this->Post->deleteAssoc(3,’Tag’,15);

You can even add more than one tag at once:
$this->Post->addAssoc(3,’Tag’,array(11,12));

Put these functions in your AppModel:
    /**
     * Adds to a HABTM association some instances
     *
     * @param integer $id The id of the record in this model
     * @param mixed $assoc_name The name of the HABTM association
     * @param mixed $assoc_id The associated id or an array of id’s to be added
     * @return boolean Success
     */
    function addAssoc($id,$assoc_name,$assoc_id)
    {
        $data=$this->_auxAssoc($id,$assoc_name);
        if (!is_array($assoc_id)) $assoc_id=array($assoc_id);
        $data[$assoc_name][$assoc_name]=am($data[$assoc_name][$assoc_name],$assoc_id);
        return $this->save($data);
    }

    /**
     * Deletes from a HABTM association some instances
     *
     * @param integer $id The id of the record in this model
     * @param mixed $assoc_name The name of the HABTM association
     * @param mixed $assoc_id The associated id or an array of id’s to be removed
     * @return boolean Success
     */
    function deleteAssoc($id,$assoc_name,$assoc_id)
    {
        $data=$this->_auxAssoc($id,$assoc_name);
        if (!is_array($assoc_id)) $assoc_id=array($assoc_id);
        $result=array();
        foreach ($data[$assoc_name][$assoc_name] as $id)
        {
            if (!in_array($id, $assoc_id)) $result[]=$id;
        }
        $data[$assoc_name][$assoc_name]=$result;
        return $this->save($data);
    }

    /**
     * Returns the data associated with a HABTM in an array
     * suitable for save without deleting the current relationships
     *
     * @param integer $id The id of the record in this model
     * @param mixed $assoc_name The name of the HABTM association
     * @return array Data array with current HABTM association intact
     */
    function _auxAssoc($id,$assoc_name)
    {
        //disable query cache
        $back_cache=$this->cacheQueries;
        $this->cacheQueries=false;

        $this->recursive=1;
        $this->unbindAll(array(‘hasAndBelongsToMany’=>array($assoc_name)));
        $data=$this->findById($id);
        $assoc_data=array();
        foreach ($data[$assoc_name] as $assoc)
        {
            $assoc_data[]=$assoc[‘id’];
        }
        unset($data[$assoc_name]);
        $data[$assoc_name][$assoc_name]=$assoc_data;

        //restore previous setting of query cache
        $this->cacheQueries=$back_cache;

        return $data;
    }