private function initialize()
    {
        $this->pdo->exec(
            'CREATE TABLE IF NOT EXISTS `'.$this->table.'` '
            .'(id INTEGER PRIMARY KEY AUTO_INCREMENT, channel VARCHAR(255),level_name VARCHAR(255), level INTEGER, message LONGTEXT, date DATETIME)'
        );
        //Read out actual columns
        $actualFields = array();
        $rs = $this->pdo->query('SELECT * FROM `'.$this->table.'` LIMIT 0');
        for ($i = 0; $i < $rs->columnCount(); $i++) {
            $col = $rs->getColumnMeta($i);
            $actualFields[] = $col['name'];
        }
        //Calculate changed entries
        $removedColumns = array_diff(
            $actualFields,
            $this->additionalFields,
            array('id', 'channel', 'level','level_name', 'message', 'date')
        );
        $addedColumns = array_diff($this->additionalFields, $actualFields);
        //Remove columns
        if (!empty($removedColumns)) {
            foreach ($removedColumns as $c) {
                $this->pdo->exec('ALTER TABLE `'.$this->table.'` DROP `'.$c.'`;');
            }
        }
        //Add columns
        if (!empty($addedColumns)) {
            foreach ($addedColumns as $c) {
                $this->pdo->exec('ALTER TABLE `'.$this->table.'` add `'.$c.'` TEXT NULL DEFAULT NULL;');
            }
        }
        //Prepare statement
        $columns = "";
        $fields = "";
        foreach ($this->additionalFields as $f) {
            $columns.= ", $f";
            $fields.= ", :$f";
        }
        $this->statement = $this->pdo->prepare(
            'INSERT INTO `'.$this->table.'` (channel, level, level_name, message, date'.$columns.')
            VALUES (:channel, :level, :level_name, :message, :date'.$fields.')'
        );
        $this->initialized = true;
    }