Audit class with Yii2

AuditActiveRecord.php

<?php
namespace app\lib;
use app\lib\Log;

/**
 * @author Andres Felipe Trujillo
 */
class AuditActiveRecord extends \yii\db\ActiveRecord
{

    private $log;

    const ACTION_CREATE = 'I';
    const ACTION_UPDATE = 'U';
    const ACTION_DELETE = 'D';

    public function __construct()
    {
        $this->log = new Log();
        $this->log->creation_date = date('Y-m-d H:i:s');
        $this->log->table = $this->tableName();
        parent::__construct();
    }
    
    /**
     * overide afterSave function
     * @access public
     * **/
    public function afterSave($insert, $changedAttributes)
    {

        if ($insert === TRUE) {
            $this->log->type = self::ACTION_CREATE;
            $this->log->record = json_encode($this->attributes,JSON_UNESCAPED_UNICODE);
            $this->log->save();
        } elseif(sizeof($changedAttributes) !== 0) {
            $pkColumnName = $this->tableSchema->primaryKey[0];
            $changedAttributes = array($pkColumnName => $this->getPrimaryKey(false)) + $changedAttributes;
            $this->log->type = self::ACTION_UPDATE;
            $this->log->record = json_encode($changedAttributes,JSON_UNESCAPED_UNICODE);
            $this->log->save();
        }
        parent::afterSave($insert, $changedAttributes);
    }
    
    /**
     * overide afterDelete function
     * @access public
     * **/
    public function afterDelete()
    {
        $this->log->type = self::ACTION_DELETE;
        $this->log->record = json_encode($this->attributes,JSON_UNESCAPED_UNICODE);
        $this->log->save();
        parent::afterDelete();
    }

}

Log.php

<?php

namespace app\lib;

use Yii;

/**
 * This is the model class for table "logs".
 *
 * @property integer $id
 * @property string $type
 * @property string $creation_date
 * @property string $table
 * @property string $record
 */
class Log extends \yii\db\ActiveRecord
{
    /**
     * @inheritdoc
     */
    public static function tableName()
    {
        return 'logs';
    }

    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            [['type', 'creation_date', 'record'], 'required'],
            [['creation_date'], 'safe'],
            [['table', 'record'], 'string'],
            [['type'], 'string', 'max' => 1]
        ];
    }

    /**
     * @inheritdoc
     */
    public function attributeLabels()
    {
        return [
            'id' => Yii::t('app', 'ID'),
            'type' => Yii::t('app', 'Type'),
            'creation_date' => Yii::t('app', 'Creation Date'),
            'table' => Yii::t('app', 'Table'),
            'record' => Yii::t('app', 'Record')
        ];
    }
}

logs.sql

CREATE TABLE logs
(
  id serial NOT NULL,
  type character varying(1) NOT NULL,
  creation_date timestamp without time zone NOT NULL,
  "table" text,
  record json NOT NULL,
  CONSTRAINT log_pk PRIMARY KEY (id)
)