Hands-On Sencha Touch 2

Chapter 7. Data Models

The model (Ext.data.Model) is a class that represents some object that your application manages. For example, you might define a model for users, products, cars, or any other real-world object that you want to model in the system.

The Ext.data.Model is part of the Sencha data package. As described in the preceding chapter, the Sencha architecture uses a pattern similar to MVC, but in the Sencha context the term model includes—besides the model itself (the structure of the data)—the layers record (the specific data) and store (a client-side cache of all records together). In this book, I will use the term model to refer to the Ext.data.Model.

A model contains fields to structure the data. For example, in the FindACab app, the CabService has three fields: name, address, and total number of cars. Each record (Ext.data.Record) is a specific CabService model object—for example, “Taxi Amsterdam,” which has a total of 14 cars. The Ext.data.Store is the whole data pool full of records, otherwise known as the client-side cache.

The fields in a model use the Ext.data.Field class. Every field can be given a data type (see Table 7-1 for an overview of all data types). Data assigned to the field will be autoconverted to the default type. For example, when a field is set to int and the data 4.8 is passed, then the data will be converted to 5. When no datatype is specified, the datatype will be set to auto, which means there is no datatype conversion at all. This might be a ...