How to load data from database to Extjs LineChart

See more:

PHP

ExtJS

I Use below code to load data from database using data.php file but its not getting data:-

var store = new Ext.data.Store({
        proxy : new Ext.data.HttpProxy({
        url : 'data.php'
        }),
        reader : new Ext.data.JsonReader({
        root : 'data',
        fields:[{date: 'date'},
          {value: 'value'}]
        })
 });
store.load();

By Using temporary data as below its getting:-

var store = new Ext.data.JsonStore({
    fields:['date', 'pcs'],
    data:[
         {date:'Jul 07', value: '1000'},
         {date:'Aug 07', value: '2000'},
         {date:'Sep 07';, value: '4000'},
         {date:'Oct 07';, value: '6000'},
         {date:'Nov 07', value: '8000'},
         {date:'Dec 07';, value: '9000'},
         {date:'Jan 08', value: '10000'},
         {date:'Feb 08', value: '12000'}
    ]
    });

And i Assinged the store value to linechart as below:-

{
                    xtype: 'linechart',
                    store: store,
                    url: '/ext/resources/charts.swf',
                    xField: 'date',
                    yField: 'value',
                   }