1 files changed, 61 insertions, 6 deletions
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md
index e1a465c64f..f8c64cbd0c 100644
--- a/guides/source/active_record_querying.md
+++ b/guides/source/active_record_querying.md
@@ -1,3 +1,5 @@
+**DO NOT READ THIS FILE IN GITHUB, GUIDES ARE PUBLISHED IN http://guides.rubyonrails.org.**
+
 Active Record Query Interface
 =============================
 
@@ -9,6 +11,7 @@ After reading this guide, you will know:
 * How to specify the order, retrieved attributes, grouping, and other properties of the found records.
 * How to use eager loading to reduce the number of database queries needed for data retrieval.
 * How to use dynamic finders methods.
+* How to use method chaining to use multiple ActiveRecord methods together.
 * How to check for the existence of particular records.
 * How to perform various calculations on Active Record models.
 * How to run EXPLAIN on relations.
@@ -87,7 +90,7 @@ The primary operation of `Model.find(options)` can be summarized as:
 * Convert the supplied options to an equivalent SQL query.
 * Fire the SQL query and retrieve the corresponding results from the database.
 * Instantiate the equivalent Ruby object of the appropriate model for every resulting row.
-* Run `after_find` callbacks, if any.
+* Run `after_find` and then `after_initialize` callbacks, if any.
 
 ### Retrieving a Single Object
 
@@ -1327,14 +1330,66 @@ You can specify an exclamation point (`!`) on the end of the dynamic finders to
 
 If you want to find both by name and locked, you can chain these finders together by simply typing "`and`" between the fields. For example, `Client.find_by_first_name_and_locked("Ryan", true)`.
 
+Understanding The Method Chaining
+---------------------------------
+
+The Active Record pattern implements [Method Chaining](http://en.wikipedia.org/wiki/Method_chaining),
+which allow us to use multiple Active Record methods together in a simple and straightforward way.
+
+You can chain methods in a statement when the previous method called returns an
+`ActiveRecord::Relation`, like `all`, `where`, and `joins`. Methods that return
+a single object (see [Retrieving a Single Object Section](#retrieving-a-single-object))
+have to be at the end of the statement.
+
+There are some examples below. This guide won't cover all the possibilities, just a few as examples.
+When an Active Record method is called, the query is not immediately generated and sent to the database,
+this just happens when the data is actually needed. So each example below generates a single query.
+
+### Retrieving filtered data from multiple tables
+
+```ruby
+Person
+  .select('people.id, people.name, comments.text')
+  .joins(:comments)
+  .where('comments.created_at > ?', 1.week.ago)
+```
+
+The result should be something like this:
+
+```sql
+SELECT people.id, people.name, comments.text
+FROM people
+INNER JOIN comments
+  ON comments.person_id = people.id
+WHERE comments.created_at = '2015-01-01'
+```
+
+### Retrieving specific data from multiple tables
+
+```ruby
+Person
+  .select('people.id, people.name, companies.name')
+  .joins(:company)
+  .find_by('people.name' => 'John') # this should be the last
+```
+
+The above should generate:
+
+```sql
+SELECT people.id, people.name, companies.name
+FROM people
+INNER JOIN companies
+  ON companies.person_id = people.id
+WHERE people.name = 'John'
+LIMIT 1
+```
+
+NOTE: Remember that, if `find_by` returns more than one registry, it will take
+just the first and ignore the others. Note the `LIMIT 1` statement above.
+
 Find or Build a New Object
 --------------------------
 
-NOTE: Some dynamic finders have been deprecated in Rails 4.0 and will be
-removed in Rails 4.1. The best practice is to use Active Record scopes
-instead. You can find the deprecation gem at
-https://github.com/rails/activerecord-deprecated_finders
-
 It's common that you need to find a record or create it if it doesn't exist. You can do that with the `find_or_create_by` and `find_or_create_by!` methods.
 
 ### `find_or_create_by`