validates_inclusion_of(*attr_names) Instance Public methods Validates whether

param_key(record_or_class) Class Public methods Returns string to use for params

as_json(options=nil) Instance Public methods Returns a

changed_attributes() Instance Public methods Returns a hash of the attributes

define_attribute_methods(*attr_names) Instance Public methods Declares the attributes

set(key, value) Instance Public methods Set messages for key to

validates_presence_of(*attr_names) Instance Public methods Validates that the

persisted?() Instance Public methods Indicates if the model is persisted.

clear() Instance Public methods Clear the error messages.

previous_changes() Instance Public methods Returns a hash of attributes that