Difference between #3 and #1 of How to automate timestamps in ActiveRecord models

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Automate timestamps in ActiveRecord models
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Tutorials
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There are dozens of ways to automate the setting of timestamps in yii
ActiveRecord models, for example with behaviours or onBeforeSave methods. I
sort of like the following method.models. Two ways you can do this
are

1. Via rules()
2. Via beforeSave()

To start off we need a database table.

    [sql]
    CREATE TABLE IF NOT EXISTS `Nodes` (
      `id` bigint(20) NOT NULL auto_increment,
      `title` varchar(255) NOT NULL,
      `created` datetime NOT NULL,
      `modified` datetime NOT NULL,
      PRIMARY KEY  (`id`)
    ) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;

Following this we'll generate the model with the Yii shell tool:

    model Node Nodes

To create the crud functionality we need to type this:

    crud Node

The magic happens in the rules of the Node classfirst way you
can do it is via your model's rules.  Here is an example.

    [php]
	/**
	 * @return array validation rules for model attributes.
	 */
	public function rules()
	{
		return array(
			array('title','length','max'=>255),
			array('title, created, modified', 'required'),
            array('modified','default','value'=>new
CDbExpression('NOW()'),'setOnEmpty'=>false,'on'=>'update'),
            array('created,modified','default','value'=>new
CDbExpression('NOW()'),'setOnEmpty'=>false,'on'=>'insert')
		);
	}

You see the two rules at the end, one changes the modified field when the
record's being updated, and the other changes both fields when the record's
being created. You'll also see the "new CDbExpression('NOW()')"
statement. This passes "NOW()" to the MySQL server and it will not be
escaped. MySQL will interpret it as a statement and not as a string. This means
that the field types could have been any other date/time type (timestamp, etc.)
and it would still work.

I find it aAnother solution is to use beforeSave() as follows:

	[php]
	public function beforeSave() {
		if ($this->isNewRecord)
			$this->created = new CDbExpression('NOW()');
		else
			$this->modified = new CDbExpression('NOW()');
			
		return parent::beforeSave();
	}

These are simple and elegant solutionsolutions to
this issue.
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  • Written by: dalip
  • Updated by: Yang He
  • Category: Tutorials
  • Yii Version: 1.1
  • Votes: +30
  • Viewed: 107,121 times
  • Created on: Feb 14, 2009
  • Last updated: Jun 29, 2012