diff options
| -rw-r--r-- | activerecord/lib/active_record/validations.rb | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb index 9219d87f5a..518b59e433 100644 --- a/activerecord/lib/active_record/validations.rb +++ b/activerecord/lib/active_record/validations.rb @@ -259,6 +259,8 @@ module ActiveRecord end + # Please do have a look at ActiveRecord::Validations::ClassMethods for a higher level of validations. + # # Active Records implement validation by overwriting Base#validate (or the variations, +validate_on_create+ and # +validate_on_update+). Each of these methods can inspect the state of the object, which usually means ensuring # that a number of attributes have a certain value (such as not empty, within a given range, matching a certain regular expression). @@ -297,8 +299,6 @@ module ActiveRecord # person.save # => true (and person is now saved in the database) # # An Errors object is automatically created for every Active Record. - # - # Please do have a look at ActiveRecord::Validations::ClassMethods for a higher level of validations. module Validations VALIDATIONS = %w( validate validate_on_create validate_on_update ) @@ -313,15 +313,26 @@ module ActiveRecord base.define_callbacks *VALIDATIONS end - # Active Record models can implement validations using three styles. The most high-level, easiest to read, - # and recommended approach is to use the declarative <tt>validates_...</tt> class methods documented below. - # At a lower level, a model can use the class methods +validate+, +validate_on_create+ and +validate_on_update+. + # Active Record classes can implement validations in several ways. The highest level, easiest to read, + # and recommended approach is to use the declarative <tt>validates_..._of</tt> class methods (and + # +validates_associated+) documented below. These are sufficient for most model validations. + # + # Slightly lower level is +validates_each+. It provides some of the same options as the purely declarative + # validation methods, but like all the lower-level approaches it requires manually adding to the errors collection + # when the record is invalid. + # + # At a yet lower level, a model can use the class methods +validate+, +validate_on_create+ and +validate_on_update+ + # to add validation methods or blocks. These are ActiveSupport::Callbacks and follow the same rules of inheritance + # and chaining. + # # The lowest level style is to define the instance methods +validate+, +validate_on_create+ and +validate_on_update+ # as documented in ActiveRecord::Validations. # # == +validate+, +validate_on_create+ and +validate_on_update+ Class Methods # - # Calls to these methods add a validation method or block to the class. + # Calls to these methods add a validation method or block to the class. Again, this approach is recommended + # only when the higher-level methods documented below (<tt>validates_..._of</tt> and +validates_associated+) are + # insufficient to handle the required validation. # # This can be done with a symbol pointing to a method: # |