Cannot use active record relation

The point is i cannot use my active record relation, even i have defined the relation. The following is my User Active Record Model.


<?php


/**

 * This is the model class for table "skat_user".

 *

 * The followings are the available columns in table 'skat_user':

 * @property integer $id

 * @property string $name

 * @property string $username

 * @property string $password

 * @property string $role

 * @property integer $skat_port_id

 *

 * The followings are the available model relations:

 * @property Port $skatPort

 * @property UserLog[] $userLogs

 */

class User extends SkatTwoActiveRecord

{

	/**

	 * Returns the static model of the specified AR class.

	 * @param string $className active record class name.

	 * @return User the static model class

	 */

	public static function model($className=__CLASS__)

	{

		return parent::model($className);

	}


	/**

	 * @return string the associated database table name

	 */

	public function tableName()

	{

		return 'skat_user';

	}


	/**

	 * @return array validation rules for model attributes.

	 */

	public function rules()

	{

		// NOTE: you should only define rules for those attributes that

		// will receive user inputs.

		return array(

			array('username, password, role', 'required'),

			array('skat_port_id', 'numerical', 'integerOnly'=>true),

			array('name, username, password', 'length', 'max'=>128),

			array('role', 'length', 'max'=>15),

      array('crated_time, modified_time', 'safe'),

			// The following rule is used by search().

			// Please remove those attributes that should not be searched.

			array('id, name, username, password, role, skat_port_id, crated_time, modified_time', 'safe', 'on'=>'search'),

		);

	}


	/**

	 * @return array relational rules.

	 */

	public function relations()

	{

		// NOTE: you may need to adjust the relation name and the related

		// class name for the relations automatically generated below.

		return array(

			'skatPort' => array(self::BELONGS_TO, 'Port', 'skat_port_id'),

			'userLogs' => array(self::HAS_MANY, 'UserLog', 'skat_user_id'),

		);

	}


	/**

	 * @return array customized attribute labels (name=>label)

	 */

	public function attributeLabels()

	{

		return array(

			'id' => 'ID',

			'name' => 'Nama',

			'username' => 'Username',

			'password' => 'Password',

			'role' => 'Level',

			'skat_port_id' => 'Pelabuhan',

      'created_time'=>'Waktu Pembuatan',

      'modified_time'=>'Waktu Perubahan',

		);

	}


	/**

	 * Retrieves a list of models based on the current search/filter conditions.

	 * @return CActiveDataProvider the data provider that can return the models based on the search/filter conditions.

	 */

	public function search()

	{

		// Warning: Please modify the following code to remove attributes that

		// should not be searched.


		$criteria=new CDbCriteria;


		$criteria->compare('id',$this->id);

		$criteria->compare('name',$this->name,true);

		$criteria->compare('username',$this->username,true);

		$criteria->compare('password',$this->password,true);

		$criteria->compare('role',$this->role,true);

		$criteria->compare('skat_port_id',$this->skat_port_id);

    $criteria->compare('created_time',$this->name);

    $criteria->compare('modified_time',$this->name);


		return new CActiveDataProvider($this, array(

			'criteria'=>$criteria,

		));

	}

	

	/**

	 * Perform one-way encryption on the password before we restore it in the database

	 */

	protected function afterValidate()

	{

		parent::afterValidate();

		$this->password=$this->encrypt($this->password);

	}

	public function encrypt($value)

	{

		return md5($value);

	}

	

	/**

	 * @return array of port for this user, indexed by port IDs

	 */ 

	public function getPortOptions()

	{ 

		$port = CHtml::listData(Port::model()->findAll(), 'id', 'name');

		return $port;

	}

	

	/**

	 * Perform fetching all data from the model

	 * @return array of all model attribute from the model

	 */

	public function getAll()

	{

		$data = self::model()->findAll();

		$result[0] = "";

   		foreach($data as $element){

    		$result[$element->id] = $element->username . " (" . $element->role . " - " . $element->skatPort->name . ")";

   		}

		return $result;

	}

  

  /**

   * Perform assertion of admin, call in component webUser

   * @return boolean     

   */   

  public function isAdmin()

	{

		return $this->role == 'admin';

	}

  

  /**

   * Perform assertion of operator_pusat, call in component webUser

   * @return boolean     

   */   

  public function isOperatorPusat()

	{

		return $this->role == 'operator_pusat';

	}

  

  /**

   * Perform assertion of operator_daerah, call in component webUser

   * @return boolean     

   */   

  public function isOperatorDaerah()

	{

		return $this->role == 'operator_daerah';

	}

}

Could you help me please? :)

Its because my relation is one to many (belongs to) and there is record that not set the value. Okay, keep coding. :D