ongoing doc

doc/readme.md

@@ -2,7 +2,7 @@
 
 I've seen many PHP ORM libraries. Most of them makes you write a new class for each item you want to keep in DB. This seems repetition of same things to me. Extending this, extending that for no different logic.
 
-Items have fields of data in similar kind and have similar relations among. So a well-written class can be used for all. If you need somthing makes things easier, this is my approach.
+Items have fields of data in similar kind and have similar relations among. So a well-written class can be used for all. If you need a library which makes things easier, this is my approach.
 
 arrayDB ORM library has only 5 classes. You mostly use a singleton of one, others used internally, that's all. Caching and keeping cache synchronised with DB is all automated. You don't need to keep track of these.
 
@@ -12,3 +12,32 @@ To start using this library, you have to do 3 simple definitions.
 - Define your MySQL access.
 - Define your cache config.
 
+## Defining data model
+
+All data model definiton is writing down an array like this:
+
+	$model=array(
+		'user'=>array(
+			'conf'=>array('len'=>7),
+			'fields'=>array(
+				'name'=>array('len'=>50)
+			),
+			'has_many'=>array(
+				'posts'=>array('type'=>'post', 'foreign_name'=>'writer')
+			),
+			'many_to_many'=>array(
+				'liked_posts'=>array('type'=>'post', 'foreign_name'=>'liker'),
+			)
+		),
+
+		'post'=>array(
+			'conf'=>array('len'=>10),
+			'fields'=>array(
+				'text'=>array('len'=>200)
+			)
+		)
+	);
+
+We have 2 items here. User and post. Users has names, many written posts and many liked posts. Posts has texts and likers.
+
+With this model, we want to