AR, named scopes, defaultScope, relations: best practices, common pitfalls and mistakes

[resurtm]

Related: #1197. This is a documentation related issue.

Current guide leads some people to misunderstand concepts of the ActiveRecord, defaultScope, named scopes, relations and using them together in different combinations. Documentation definitely lacks in best practices, pitfalls and mistakes of using them.

Examples to be explained:

1. Default scope is not a real scope as one may think. It can't be disabled at all in any circumstances.
2. Using with inside default scope or named scope is a bad practice.
3. Using CHttpRequest component in models is also not the best idea and reduces code testing aptitude.
4. ...

[ErikMinekus]

I'm fairly new to Yii, and I was also doing as described in #1197, being under the impression using with inside scopes is a good practice. Is there any information (forum posts or wiki articles) we can reference right now as to why this is bad practice, or will we have to wait until the documentation is updated?

[resurtm]

@ErikMinekus, i dare to offer you a describing note. Perhaps it contains mistakes, but in general conveys the idea. (Comments and refinements are appreciated.)

[rawtaz]

@resurtm Someone on the IRC linked to the Google Docs doc you referenced above, but it doesn't show any contents unless one is logged in. Can you please publish it in a more neutral way, e.g. a gist or something?

[resurtm]

@rawtaz, sure: https://gist.github.com/resurtm/5289938

[creocoder]

@resurtm

Using CWebUser component in models is also not the best idea and reduces code testing aptitude.

What if model contains code like:

    protected function beforeSave()
    {
        if(!parent::beforeSave())
            return false;

        if($this->isNewRecord)
            $this->created_by_id=Yii::app()->user->id;
        else
            $this->updated_by_id=Yii::app()->user->id;

        return true;
    }

What wrong here?

[resurtm]

@creocoder, nothing wrong. It was my mistake, sorry. I actually meant CHttpRequest application component. One day i came across the following code:

protected function beforeSave()
{
    if(!parent::beforeSave())
    {
        return false;
    }

    $this->user_agent=Yii::app()->request->userAgent; // 0_o?
    $this->remote_addr=Yii::app()->request->userHostAddress; // 0_o?

    return true;
}

It is definitely a bad practice. I've changed the issue description.