Sencha Touch SQL proxy - sql

Question

I am using SQL proxy in my Sencha Touch 2 app and I am able to store and retrieve data offline.
What I cannot do and what the Sencha documentation does not seem to provide is how do I customize the Sencha SQL store.
For eg, to create a SQL based store, I did the following -
Ext.define("MyApp.model.Customer", {
extend: "Ext.data.Model",
config: {
fields: [
{name: 'id', type: 'int'},
{name: 'name', type: 'string'},
{name: 'age', type: 'string'}
],
proxy: {
type: "sql",
database: "MyDb",
}
}
});
1. Now, how do i specify the size of the database ?
2. How do I specify constraints on the fields like unique, primary key etc ?
Say, I have 4 columns in my database :
pid, name, age, phone
I want to have a primary key for multiple fields : (pid, name)
If I was creating a table via SQL query, I would do something like -
CREATE TABLE Persons
(
pid int,
name varchar(255),
age int,
phone int,
primary key (pid,name)
);
Now how do I achieve the same via model ?
3. If I want to interact with the database via SQL query, I do the following -
var query = "SELECT * from CUSTOMER";
var db = openDatabase('MyDb', '1.0', 'MyDb', 2 * 1024 * 1024);
db.transaction(function (tx) {
tx.executeSql(query, [], function (tx, results) {
// do something here
}, null);
});
Is this the best way to do it?