describe Single Collection Inheritance

CHANGELOG.md

@@ -1,5 +1,6 @@
-## 1.12.2@DEV
+## 1.12.2(2015-01-13)
   * `Operator` refactoring and bugfixes
+  * Fix Collection::update when update data set as array
 
 ## 1.12.1 (2015-01-10)
   * Set `Structure` to document as embedded document

README.md

@@ -371,6 +371,8 @@ echo $col1->getOption('regexp')[1]; // 42
 
 ### Document schema and validating
 
+#### Custom document class
+
 Custom document class may be useful when required some processing of date on load, getting or save. Custom document class must extend `\Sokil\Mongo\Document`.
 
 ```php
@@ -393,6 +395,13 @@ class CustomCollection extends \Sokil\Mongo\Collection
 }
 ```
 
+#### Single Collection Inheritance
+
+Often useful to have different document classes, which store data in single collection.
+For example you have products in your shop `Song` and `VideoClip`, which inherit abstract `Product`.
+They have same fields like author or duration, but may also have other different fields and
+behaviors. This situation described in example [Product Catalog](http://docs.mongodb.org/ecosystem/use-cases/product-catalog/).
+
 You may flexibly configure document's class in `\Sokil\Mongo\Collection::getDocumentClassName()` relatively to concrete document's data:
 
 ```php