jackhammer013 jackhammer013 - 5 months ago 46
Javascript Question

How to use database query with JOIN in server-side processing mode

I am using jQuery DataTables for my view list. I used server-side processing mode which works perfectly especially for huge datasets. But my problem is that I am only able to do this using single database table.

What about using custom query using multiple tables with

JOIN
without changing too much is my code?

So I have this:

HTML

<table id="CustomerList" class="table table-striped table-bordered" cellspacing="0" width="100%">
<thead>
<tr>
<th colspan="7"> <center>Customer Information<center></th>
<th colspan="1"> <center>Actions<center></th>
</tr>
<tr>
<th>ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Gender</th>
<th>Phone Number</th>
<th>Country</th>
<th>Postcode</th>
<th>Edit</th>
<!-- <th>Edit</th>
<th>Delete</th> -->
</tr>
</thead>
<tbody>
</tbody>
</table>


Ajax

<script type="text/javascript">
$(document).ready(function() {
$.fn.dataTable.ext.legacy.ajax = true;
var table = $('#CustomerList').DataTable( {
"processing": true,
"serverSide": true,
"ajax": "api/customer/all",
"columnDefs": [
{
"targets": 7,
"render": function(data, type, row, meta){
// return '<a href="/qms/public/customer/' + row[0] + '/edit">Edit</a>';
return "<a class='btn btn-small btn-info' href='<?php echo URL::to('customer').'/';?>"+row[0]+"/edit'><span class='glyphicon glyphicon glyphicon-edit' aria-hidden='true'></span></a>";
}
}
]
});
var tt = new $.fn.dataTable.TableTools( $('#CustomerList').DataTable() );
$( tt.fnContainer() ).insertBefore('div.dataTables_wrapper');
});




Controller

public function apiGetCustomers()
{
/*=================================================================*/
/*
* Script: DataTables server-side script for PHP and PostgreSQL
* Copyright: 2010 - Allan Jardine
* License: GPL v2 or BSD (3-point)
*/

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Easy set variables
*/

/* Array of database columns which should be read and sent back to DataTables. Use a space where
* you want to insert a non-database field (for example a counter or static image)
*/
$aColumns = array('id', 'firstname', 'lastname', 'gender', 'phone_num', 'country', 'postcode' );

/* Indexed column (used for fast and accurate table cardinality) */
$sIndexColumn = "phone_num";

/* DB table to use */
$sTable = "customers";

/* Database connection information */
$gaSql['user'] = "postgres";
$gaSql['password'] = "postgres";
$gaSql['db'] = "qms";
$gaSql['server'] = "localhost";



/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* If you just want to use the basic configuration for DataTables with PHP server-side, there is
* no need to edit below this line
*/

/*
* DB connection
*/
$gaSql['link'] = pg_connect(
" host=".$gaSql['server'].
" dbname=".$gaSql['db'].
" user=".$gaSql['user'].
" password=".$gaSql['password']
) or die('Could not connect: ' . pg_last_error());


/*
* Paging
*/
$sLimit = "";
if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' )
{
$sLimit = "LIMIT ".intval( $_GET['iDisplayLength'] )." OFFSET ".
intval( $_GET['iDisplayStart'] );
}


/*
* Ordering
*/
if ( isset( $_GET['iSortCol_0'] ) )
{
$sOrder = "ORDER BY ";
for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ )
{
if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" )
{
$sOrder .= $aColumns[ intval( $_GET['iSortCol_'.$i] ) ]."
".($_GET['sSortDir_'.$i]==='asc' ? 'asc' : 'desc').", ";
}
}

$sOrder = substr_replace( $sOrder, "", -2 );
if ( $sOrder == "ORDER BY" )
{
$sOrder = "";
}
}

/*
* Filtering
* NOTE This assumes that the field that is being searched on is a string typed field (ie. one
* on which ILIKE can be used). Boolean fields etc will need a modification here.
*/
$sWhere = "";
if ( $_GET['sSearch'] != "" )
{
$sWhere = "WHERE (";
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
if ( $_GET['bSearchable_'.$i] == "true" )
{
if($aColumns[$i] != 'id') // Exclude ID for filtering
{
$sWhere .= $aColumns[$i]." ILIKE '%".pg_escape_string( $_GET['sSearch'] )."%' OR ";
}
}
}
$sWhere = substr_replace( $sWhere, "", -3 );
$sWhere .= ")";
}

/* Individual column filtering */
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
if ( $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' )
{
if ( $sWhere == "" )
{
$sWhere = "WHERE ";
}
else
{
$sWhere .= " AND ";
}
$sWhere .= $aColumns[$i]." ILIKE '%".pg_escape_string($_GET['sSearch_'.$i])."%' ";
}
}


$sQuery = "
SELECT ".str_replace(" , ", " ", implode(", ", $aColumns))."
FROM $sTable
$sWhere
$sOrder
$sLimit
";

$rResult = pg_query( $gaSql['link'], $sQuery ) or die(pg_last_error());

$sQuery = "
SELECT $sIndexColumn
FROM $sTable
";
$rResultTotal = pg_query( $gaSql['link'], $sQuery ) or die(pg_last_error());
$iTotal = pg_num_rows($rResultTotal);
pg_free_result( $rResultTotal );

if ( $sWhere != "" )
{
$sQuery = "
SELECT $sIndexColumn
FROM $sTable
$sWhere
";
$rResultFilterTotal = pg_query( $gaSql['link'], $sQuery ) or die(pg_last_error());
$iFilteredTotal = pg_num_rows($rResultFilterTotal);
pg_free_result( $rResultFilterTotal );
}
else
{
$iFilteredTotal = $iTotal;
}

/*
* Output
*/
$output = array(
"sEcho" => intval($_GET['sEcho']),
"iTotalRecords" => $iTotal,
"iTotalDisplayRecords" => $iFilteredTotal,
"aaData" => array()
);

while ( $aRow = pg_fetch_array($rResult, null, PGSQL_ASSOC) )
{
$row = array();
for ( $i=0 ; $i<count($aColumns) ; $i++ )
{
if ( $aColumns[$i] == "version" )
{
/* Special output formatting for 'version' column */
$row[] = ($aRow[ $aColumns[$i] ]=="0") ? '-' : $aRow[ $aColumns[$i] ];
}
else if ( $aColumns[$i] != ' ' )
{
/* General output */
$row[] = $aRow[ $aColumns[$i] ];
}
}
$output['aaData'][] = $row;
}

echo json_encode( $output );

// Free resultset
pg_free_result( $rResult );

// Closing connection
pg_close( $gaSql['link'] );


}


In my controller you can see the
$aColumns
which contains the table column that I want to get in the table
customers


What if I want a custom query to fetch data like:

$query = "SELECT a.id as crmid, b.name, a.title, a.firstname, a.surname, a.disposition, a.gross, a.created_at, a.phone_num FROM forms a INNER JOIN users b ON a.agent_id = b.id;";


So I have inner joins instead of one table only.

Answer

There is a trick to use JOIN without modifying the code too much.

Change this line:

$sTable = "customers";

to:

$sTable = 
   "( 
      SELECT a.id AS crmid, b.name 
      FROM forms a 
      INNER JOIN users b ON a.agent_id = b.id 
    ) table";

I simplified the query above only for the sake of code clarity. Just make sure that all column names are unique, otherwise use aliases where needed.

Then use column names/aliases in $aColumns variable. For the query above it wold be

$aColumns = array('crmid', 'name');