1 files changed, 26 insertions, 26 deletions
diff --git a/guides/source/active_record_validations.md b/guides/source/active_record_validations.md
index 67cc6a4db3..de26a9bd6d 100644
--- a/guides/source/active_record_validations.md
+++ b/guides/source/active_record_validations.md
@@ -231,9 +231,9 @@ Errors](#working-with-validation-errors) section.
 
 ### `errors.details`
 
-To check what validator type was used on invalid attribute, you can use
-`errors.details[:attribute]`. It returns array of hashes where under `:error`
- key you will find symbol of used validator.
+To check which validations failed on an invalid attribute, you can use
+`errors.details[:attribute]`. It returns an array of hashes with an `:error`
+key to get the symbol of the validator:
 
 ```ruby
 class Person < ActiveRecord::Base
@@ -245,7 +245,7 @@ end
 >> person.errors.details[:name] #=> [{error: :blank}]
 ```
 
-Using `details` with custom validators are covered in the [Working with
+Using `details` with custom validators is covered in the [Working with
 Validation Errors](#working-with-validation-errors) section.
 
 Validation Helpers
@@ -606,9 +606,7 @@ This helper validates that the attribute's value is unique right before the
 object gets saved. It does not create a uniqueness constraint in the database,
 so it may happen that two different database connections create two records
 with the same value for a column that you intend to be unique. To avoid that,
-you must create a unique index on both columns in your database. See
-[the MySQL manual](http://dev.mysql.com/doc/refman/5.6/en/multiple-column-indexes.html)
-for more details about multiple column indexes.
+you must create a unique index on that column in your database.
 
 ```ruby
 class Account < ActiveRecord::Base
@@ -628,6 +626,7 @@ class Holiday < ActiveRecord::Base
     message: "should happen once per year" }
 end
 ```
+Should you wish to create a database constraint to prevent possible violations of a uniqueness validation using the `:scope` option, you must create a unique index on both columns in your database. See [the MySQL manual](http://dev.mysql.com/doc/refman/5.6/en/multiple-column-indexes.html) for more details about multiple column indexes or [the PostgreSQL manual](http://www.postgresql.org/docs/9.4/static/ddl-constraints.html) for examples of unique constraints that refer to a group of columns.
 
 There is also a `:case_sensitive` option that you can use to define whether the
 uniqueness constraint will be case sensitive or not. This option defaults to
@@ -1094,39 +1093,40 @@ Another way to do this is using `[]=` setter
 
 ### `errors.details`
 
-You can add validator type to details hash when using `errors.add` method.
+You can specify a validator type to the returned error details hash using the
+`errors.add` method.
 
 ```ruby
-  class Person < ActiveRecord::Base
-    def a_method_used_for_validation_purposes
-      errors.add(:name, :invalid_characters)
-    end
+class Person < ActiveRecord::Base
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters)
   end
+end
 
-  person = Person.create(name: "!@#")
+person = Person.create(name: "!@#")
 
-  person.errors.details[:name]
-   # => [{error: :invalid_characters}]
+person.errors.details[:name]
+# => [{error: :invalid_characters}]
 ```
 
-To improve error details to contain not allowed characters set, you can
-pass additional options to `errors.add` method.
+To improve the error details to contain the unallowed characters set for instance,
+you can pass additional keys to `errors.add`.
 
 ```ruby
-  class Person < ActiveRecord::Base
-    def a_method_used_for_validation_purposes
-      errors.add(:name, :invalid_characters, not_allowed: "!@#%*()_-+=")
-    end
+class Person < ActiveRecord::Base
+  def a_method_used_for_validation_purposes
+    errors.add(:name, :invalid_characters, not_allowed: "!@#%*()_-+=")
   end
+end
 
-  person = Person.create(name: "!@#")
+person = Person.create(name: "!@#")
 
-  person.errors.details[:name]
-  # => [{error: :invalid_characters, not_allowed: "!@#%*()_-+="}]
+person.errors.details[:name]
+# => [{error: :invalid_characters, not_allowed: "!@#%*()_-+="}]
 ```
 
-All built in Rails validators populate details hash with corresponding
-validator types.
+All built in Rails validators populate the details hash with the corresponding
+validator type.
 
 ### `errors[:base]`