Question

exports.definition = {

    config : {
        // table schema and adapter information
    },

    extendModel: function(Model) {      
        _.extend(Model.prototype, {
            // Extend, override or implement the Backbone.Model methods                     
        });
        return Model;
    },

    extendCollection: function(Collection) {        
        _.extend(Collection.prototype, {

            // Implement the comparator method.
            comparator : function(book) {
                return book.get('title');
            }

        }); // end extend

        return Collection;
    }
}

Where should i specify url property to communicate with my rest service.

http://docs.appcelerator.com/titanium/latest/#!/guide/Alloy_Models

Answer 1

exports.definition = {
    config: {
            "columns": {
                "username": "",
                "password": ""
            },
            "defaults": {
                "username": "-",
                "password": "-"
            },
            "adapter": {
                "type": "restapi",
                "collection_name": "user"
            }
        },

    extendModel: function(Model) {      
        _.extend(Model.prototype, {
            **urlRoot**:'',
            checkLogin: function(){

            } 
        });

        return Model;
    },

    extendCollection: function(Collection) {        
        _.extend(Collection.prototype, {
            // Extend, override or implement Backbone.Collection 
        });

        return Collection;
    }
}

Backbone.sync method executes RESTful JSON requests to a URL specified by the Model.urlRoot or Collection.url attribute, when these classes are created. You can either specify in the Model or Collection.