CDbStatePersister

protected function createTable()
{
    try
    {
        $command=$this->db->createCommand();
        $command->createTable($this->stateTableName,array(
            $this->keyField=>'string NOT NULL',
            $this->valueField=>'text NOT NULL',
            'PRIMARY KEY ('.$this->db->quoteColumnName($this->keyField).')'
        ));
    }
    catch (CDbException $e)
    {
        throw new CException(Yii::t('yii','Can\'t create state persister table. Check CREATE privilege for \'{db}\' connection user or create table manually with SQL: {sql}.',array('{db}'=>$this->dbComponent,'{sql}'=>$command->text ) ) );
    }
}

public function exists()
{
    $command=$this->db->createCommand();
    $command=$command->select($this->keyField)->from($this->stateTableName);
    $command=$command->where($this->db->quoteColumnName($this->keyField).'=:key',array(
        ':key'=>Yii::app()->name
    ));
    return $command->queryScalar();
}

public function init()
{
    parent::init();
    if($this->stateTableName===null)
        throw new CException(Yii::t('yii', 'stateTableName param cannot be null.'));
    $this->db=Yii::app()->getComponent($this->dbComponent);
    if($this->db===null)
        throw new CException(Yii::t('yii', '\'{db}\' component doesn\'t exist.',array(
            '{db}'=>$this->dbComponent
        )));
    if(!($this->db instanceof CDbConnection))
        throw new CException(Yii::t ('yii', '\'{db}\' component is not a valid CDbConnection instance.',array(
            '{db}'=>$this->dbComponent
        )));
    if($this->db->schema->getTable($this->stateTableName,true)===null)
        $this->createTable();
}

public function load()
{
    $command=$this->db->createCommand();
    $command=$command->select($this->valueField)->from($this->stateTableName);
    $command=$command->where($this->db->quoteColumnName($this->keyField).'=:key',array(
        ':key'=>Yii::app()->name
    ));
    $state=$command->queryScalar();
    if(false!==$state)
        return unserialize($state);
    else
        return null;
}

public function save($state)
{
    $command=$this->db->createCommand();
    if(false===$this->exists())
        return $command->insert($this->stateTableName,array(
            $this->keyField=>Yii::app()->name,
            $this->valueField=>serialize($state)
        ));
    else
        return $command->update($this->stateTableName,array($this->valueField=>serialize($state)),
            $this->db->quoteColumnName($this->keyField).'=:key',
            array(':key'=>Yii::app()->name)
    );
}