Adding data to ExtJS grid from PostgreSQL

Loading data from a PostgreSQL database into an application is useful more so if there will be frequent changes on the data stored in the databases. The data is loaded from the database when the application is loading. Any changes on the data are reflected into the grid carrying our data in the application.

I will demonstrate using PHP and ExtJS on how to query a database and return the data into a JSON format that will be used in our JavaScript application.

First, we write a script that will query our database in PHP (data.php)

//data.php

$db = pg_connect(“host=somehost port=someport dbname=**** user=**** password=****”) or die(‘could not connect:’.pg_last_error());

$result = pg_query($db, “SELECT *,ST_AsGeoJSON(geom) FROM Africa”) or die(“Data load failed:”.pg_last_error());

$rows = array(

         ‘type’      => ‘FeatureCollection’,

        ‘features’ => array()

);

while($r = pg_fetch_assoc($result))

                {

                                $rows[] = $r;

                }

echo json_encode($rows);

?>

This will return our result as a JSON file.We then define a path in our JavaScript file to point to the query results

var mydata = “data.php”;

Secondly, we create a JSON store to read our query result above.This will be done using the ExtJS library Ext.data.JsonStore()

var store = new Ext.data.JsonStore({

                         proxy: {

                                          type: ‘ajax’,

                                          url:mydata,

                                          reader: {

                                                       type: ‘json’,

                                           }

                                  },

                         fields: [

                                     {name: ‘gid’, type: ‘int’},

                                       ‘cntry_name’, ‘sovereign’, ‘pop_cntry’,’curr_type’,’landlocked’

                                 ]

            });

We then load our store with data from mydata

store.load();

Lastly, we define our grid that will display the data

var grid = new Ext.grid.GridPanel({

                        store: store,

                        columns: [

                               {header: ‘gid’, width: 50, sortable: true, dataIndex: ‘gid’},

                               {header: ‘Country Name’, width: 100, sortable: true, dataIndex: ‘cntry_name’},

                               {header: ‘Sovereign’, width: 100, sortable: true, dataIndex: ‘sovereign’},

                               {header: ‘Population’, width: 250, sortable: true, dataIndex: ‘pop_cntry’},

                               {header: ‘Currency’, width: 250, sortable: true, dataIndex: ‘curr_type’},

                               {header: ‘Landlocked’, width: 250, sortable: true, dataIndex: ‘landlocked’}

                          ],

                         stripeRows: true,

                         columnLines:true,

                         title:’DB Grid’

    });