Ext JS 4 is still in nascent stages so far model associations are concerned.
It currently has rudimentary Has-Many and Belongs-To relationships only.
So what do you do if you have pretty complex model with multiple levels of nested associations which also include Many-to-Many instances.
Work around – Use Has-Many Through relationship aka Ruby on Rails.
For example –
Product has many Categories. Category has many products.
Classic case of Many-to-many.
ROR happily supports it as its an old man in this arena while ExtJs 4 is the new kid on the block.
Work around in Ext JS –
Product has many prod-categories.
Category has many prod-categories.
Prod-category belongs to Product.
Prod-category belongs to Category.
And we are good to go…