the ActiveRecord class name that should be used to look for the attribute value being validated. Defaults to null, meaning using the class of the object currently being validated. You may use path alias to reference a class name here.

See

Since

the ActiveRecord class attribute name that should be used to look for the attribute value being validated. Defaults to null, meaning using the name of the attribute being validated.

See

Since

additional query criteria. This will be combined with the condition that checks if the attribute value exists in the corresponding table column. This array will be used to instantiate a Criteria object.

Since

the user-defined error message. The placeholders "{attribute}" and "{value}" are recognized, which will be replaced with the actual attribute name and value, respectively.