Added documentation for validates_presence_of

2 files changed, 50 insertions, 0 deletions

diff --git a/railties/doc/guides/html/activerecord_validations_callbacks.html b/railties/doc/guides/html/activerecord_validations_callbacks.html
index 6feaae68ea..2e5044eb6e 100644
--- a/railties/doc/guides/html/activerecord_validations_callbacks.html
+++ b/railties/doc/guides/html/activerecord_validations_callbacks.html
@@ -539,6 +539,35 @@ http://www.gnu.org/software/src-highlite -->
 </tt></pre></div></div>

 <div class="para"><p>The default error message for <tt>validates_numericallity_of</tt> is "<em>is not a number</em>".</p></div>

 <h3 id="_the_tt_validates_presence_of_tt_helper">3.10. The <tt>validates_presence_of</tt> helper</h3>

+<div class="para"><p>This helper validates that the attributes are not empty. It uses the <tt>blank?</tt> method to check if the value is either <tt>nil</tt> or an empty string (if the string has only spaces, it will still be considered empty).</p></div>

+<div class="listingblock">

+<div class="content"><!-- Generator: GNU source-highlight 2.9

+by Lorenzo Bettini

+http://www.lorenzobettini.it

+http://www.gnu.org/software/src-highlite -->

+<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Person <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base

+  validates_presence_of <span style="color: #990000">:</span>name<span style="color: #990000">,</span> <span style="color: #990000">:</span>login<span style="color: #990000">,</span> <span style="color: #990000">:</span>email

+<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>

+</tt></pre></div></div>

+<div class="admonitionblock">

+<table><tr>

+<td class="icon">

+<img src="./images/icons/note.png" alt="Note" />

+</td>

+<td class="content">If you want to be sure that an association is present, you'll need to test if the foreign key used to map the association is present, and not the associated object itself.</td>

+</tr></table>

+</div>

+<div class="listingblock">

+<div class="content"><!-- Generator: GNU source-highlight 2.9

+by Lorenzo Bettini

+http://www.lorenzobettini.it

+http://www.gnu.org/software/src-highlite -->

+<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> LineItem <span style="color: #990000">&lt;</span> ActiveRecord<span style="color: #990000">::</span>Base

+  belongs_to <span style="color: #990000">:</span>order

+  validates_presence_of <span style="color: #990000">:</span>order_id

+<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>

+</tt></pre></div></div>

+<div class="para"><p>The default error message for <tt>validates_presence_of</tt> is "<em>can't be empty</em>".</p></div>

 <h3 id="_the_tt_validates_size_of_tt_helper">3.11. The <tt>validates_size_of</tt> helper</h3>

 <h3 id="_the_validates_uniqueness_of_helper">3.12. The validates_uniqueness_of+ helper</h3>

 </div>

diff --git a/railties/doc/guides/source/activerecord_validations_callbacks.txt b/railties/doc/guides/source/activerecord_validations_callbacks.txt
index b26ebfed41..568ab8bc23 100644
--- a/railties/doc/guides/source/activerecord_validations_callbacks.txt
+++ b/railties/doc/guides/source/activerecord_validations_callbacks.txt
@@ -237,6 +237,27 @@ The default error message for +validates_numericallity_of+ is "_is not a number_
 
 === The +validates_presence_of+ helper
 
+This helper validates that the attributes are not empty. It uses the +blank?+ method to check if the value is either +nil+ or an empty string (if the string has only spaces, it will still be considered empty). 
+
+[source, ruby]
+------------------------------------------------------------------
+class Person < ActiveRecord::Base
+  validates_presence_of :name, :login, :email
+end
+------------------------------------------------------------------
+
+NOTE: If you want to be sure that an association is present, you'll need to test if the foreign key used to map the association is present, and not the associated object itself.
+
+[source, ruby]
+------------------------------------------------------------------
+class LineItem < ActiveRecord::Base
+  belongs_to :order
+  validates_presence_of :order_id
+end
+------------------------------------------------------------------
+
+The default error message for +validates_presence_of+ is "_can't be empty_".
+
 === The +validates_size_of+ helper
 
 === The validates_uniqueness_of+ helper