There's no such table when create new alloy model.

Before creating the model object I always drop tables first like this

db.execute(' DROP TABLE IF EXISTS Products;');
db.execute(' DROP TABLE IF EXISTS Models;');

but when I try to create model from Products or Models, it always throws an exception "There's no such table" exception

var products = Alloy.createCollection('Products');
var product = Alloy.createModel('Products', {
                    fields..
});
product.save();
products.fetch();

, and I know that when creating a model it creates table in DB automatically, so what am I doing wrong?

I'm using titanium sdk 3.4.1 thanks..