diff options
Diffstat (limited to 'activerecord/lib')
-rw-r--r-- | activerecord/lib/active_record/base.rb | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index f978fbd0a4..a96da388dc 100644 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -140,8 +140,7 @@ module ActiveRecord #:nodoc: # == Attribute query methods # # In addition to the basic accessors, query methods are also automatically available on the Active Record object. - # Query methods allow you to test whether an attribute value is present. - # For numeric values, present is defined as non-zero. + # A query method returns true or false depending on the value of the attribute. # # For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call # to determine whether the user has a name: @@ -152,6 +151,41 @@ module ActiveRecord #:nodoc: # anonymous = User.new(name: "") # anonymous.name? # => false # + # When an attribute's value is nil, the query method will return false: + # + # user = User.new(name: nil) + # user.name? # => false + # + # When the value is not nil, whether true or false is returned depends on the + # attribute's underlying class. + # + # When used on a boolean attribute, the query method returns false if the + # attribute is false, or true if it is true: + # + # user = User.new(has_joined_newsletter: false) + # user.has_joined_newsletter? # => false + # + # user.has_joined_newsletter = true + # user.has_joined_newsletter? # => true + # + # In other words, it returns the value of the boolean attribute. + # + # For numeric attributes, the query method will return false if the value is + # zero, or true otherwise: + # + # user = User.new(age: 0) + # user.age? # => false + # + # user.age = 25 + # user.age? # => true + # + # With other classes, the query method returns true if the value is present + # (more specifically, it returns true if it is not blank, as defined by + # <tt>Object#blank?</tt>). For instance, as seen above, a non-blank String + # would cause the query method to return true, while a blank String would + # return false. A String is considered blank when it has a length of zero, + # or contains only whitespace. + # # == Accessing attributes before they have been typecasted # # Sometimes you want to be able to read the raw attribute data without having the column-determined |