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    Title
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    Understanding "Safe" Validation Rules
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    FAQs
    Yii version
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    Tags
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    Forms, Validation, Safe, Massive Assignment, understanding
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    A common source of confusion among new Yii users is how the `'safe'` validator works, how it works with other validators, and why it's necessary in the first place. This article means to clear up this confusion, as well as explain the notion of Massive Assignment.
Summary: A model's validation rules serve **two** purposes:
1. 
IEnsure that fields entered in a form are entered properly
2. Define which form fields are allowed to be assigned to a $model variable[...]
Validation Rules
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The obvious purpose for validators is to iensure that users enter good data into application forms.
If a field should be no more than 16 characters long, if it should reflect a unique value in a table, or it must look like an email address, Yii provides a rich set of validators to help enforce form validation.[...]
Yii takes the conservative approach that attributes are assumed to be unsafe unless the developer explicitly makes them so (a "default deny" paradigm), rather than the easier but more dangerous "default allow".
It's wise to review the Rules in your model from time to time to iensure that you're not allowing things you should not (especially when scenarios are in play), because it's not uncommon to wildly mark things as safe during a bout of validation problems without realizing that this actaully reduces the security of the application.
 
 
Russian Version: [Правило валидации "safe", для тех, кто в танке](http://phptime.ru/blog/yii/23.html)