Yii default validator Aliases

Below is the complete list of predefined Yii validator aliases:

• boolean:
  alias of CBooleanValidator,
  ensuring the attribute has a value that is either CBooleanValidator::trueValue
  or CBooleanValidator::falseValue.
• captcha:
  alias of CCaptchaValidator,
  ensuring the attribute is equal to the verification code displayed in a CAPTCHA.
  
  
• compare:
  alias of CCompareValidator,
  ensuring the attribute is equal to another attribute or constant.
• email:
  alias of CEmailValidator,
  ensuring the attribute is a valid email address.
• date:
  alias of CDateValidator,
  ensuring the attribute represents a valid date, time, or datetime value.
  
  

• default:
  alias of CDefaultValueValidator,
  assigning a default value to the specified attributes. 
•  exist:
  alias of CExistValidator,
  ensuring the attribute value can be found in the specified table column. 
• file:
  alias of CFileValidator,
  ensuring the attribute contains the name of an uploaded file. 
• filter:
  alias of CFilterValidator,
  transforming the attribute with a filter. 
• in:
  alias of CRangeValidator,
  ensuring the data is among a pre-specified list of values. 
• length:
  alias of CStringValidator,
  ensuring the length of the data is within certain range.
•  
• match:
  alias of CRegularExpressionValidator,
  ensuring the data matches a regular expression. 
•  numerical:
  alias of CNumberValidator,
  ensuring the data is a valid number. 
•  required:
  alias of CRequiredValidator,
  ensuring the attribute is not empty. 
• type:
  alias of CTypeValidator,
  ensuring the attribute is of specific data type. 
• unique:
  alias of CUniqueValidator,
  ensuring the data is unique in a database table column. 
• url:
  alias of CUrlValidator,
  ensuring the data is a valid URL. 
•  unsafe : CUnsafeValidator 
• safe : CSafeValidator

Source:  http://www.yiiframework.com/wiki/56/reference-model-rules-validation/