Dynamically get column names in $aColumns arrary in datatables

First I'll mention what I am trying to achieve. I am using CodeIgniter framework of PHP. I have 5 tables in my database and I want to display them in Datatables format on a button click on the display page. I am using server side processing php as data source. So at first I made the code for displaying only one table in Datatable format and was successful in it. Now I want to display one table at a time out of 5 on button click event. But $aColumns length should be equal to number of columns defined in HTML table. Now considering marks tabe, it has 4 columns student_id, exam_id, subject_id and marks_achieved. Now another table is branch and has 2 columns only branch_id and branch_name. So I cannot increase or decrease tags in HTML dynamically so I am confused. Also I am using this source to create datatables. You can check my getTable() function here.

jQuery:

$(document).ready(function()
{
$('#datatable').dataTable({
    "sPaginationType":"full_numbers",
    "bJQueryUI":true,
    "bProcessing": true,
    "bServerSide": true,
    "sServerMethod": "GET",
    "sAjaxSource": "datatable/getTable",
    "iDisplayStart": 0,
    "iDisplayLength": 10,
    "aLengthMenu": [[10, 25, 50, -1], [10, 25, 50, "All"]],
    "aaSorting": [[0, 'asc']],
    "aoColumns": [
        { "bVisible": true, "bSearchable": true, "bSortable": true },
        { "bVisible": true, "bSearchable": true, "bSortable": true },
        { "bVisible": true, "bSearchable": true, "bSortable": true },
        { "bVisible": true, "bSearchable": true, "bSortable": true }
        ]
})

$('input[type=button]').bind('click', function(){
        var param = $(this).attr('id');
            data = param + '=1';

        $.ajax({
            type: 'POST',
            url: 'datatable', 
            data: data                
        }).done(function( data ) { 
            console.log(data);
            $('#display_area').html(data); 
        });
    })
    });

HTML:

<script type="text/javascript" src="../js/jquery.js"></script>
<script type="text/javascript" src="../js/javascript.js"></script>
<script type="text/javascript" src="../js/jquery.dataTables.min.js"></script>
</head>
<body id="dt_example">
<form action="" method="post">
<input type="button" id="display_branch" name="display_branch" value="Display Branch Table" >
<input type="button" id="display_marks" name="display_marks" value="Display Marks Table" >
</form>   
<div id="container">
<div id="demo">
<table id="datatable" cellpadding="0" cellspacing="0" border="0" width="100%">
<thead>
    <tr>
        <th>Student ID</th>
        <th>Exam ID</th>
        <th>Subject ID</th>
        <th>Marks Achieved</th>
    </tr>
</thead>
<tbody>
    <tr>
        <td></td>
        <td></td>
        <td></td>
        <td></td>
    </tr>
</tbody>
<tfoot></tfoot>
</table>
</div>
<div class="spacer"></div>
</div>
</body>
</html>

To get the columns dynamically I have made this change as shown below in datatable.php but it is not working. What is wrong here or I should try some other approach ?

   if(isset($_POST['display_marks']))
    {
        $aColumns = array('student_id', 'exam_id', 'subject_id', 'marks_achieved');
        $sTable = 'marks';
    }
    if(isset($_POST['display_branch']))
    {
        $aColumns = array('branch_id', 'branch_name');
        $sTable = 'branch';
    }

EDIT: The solution posted by user1190992 works but the whole approach is changed. And in that I want to sanitize the headers of the columns. "branch_id" is displayed instead I want to display Branch ID. How can I perform this sanitization ?

This is a very simple way for creating HTML from JSON data dynamically. It doesn't use server side processing though.

JavaScript

$(document).ready(function() {
    $(".abutton").click(function() {
        $('#myDatatable_wrapper').detach(); //Remove existing table
        var table = '<table id="myDatatable" class="table"><thead><tr>';
        $.ajax({
            url: 'dt.php',
            data: "table_id="+$(this).attr("id"),
            type: "POST",
            success: function (data) {
                $.each(data.aoColumns, function(key, value) {
                    table += "<th>"+value+"</th>";
                });
                table += "</tr></thead><tbody>";
                $.each(data.aaData, function(key, row) {
                    table += "<tr>";
                    $.each(row, function(key, fieldValue) {
                        table += "<td>"+fieldValue+"</td>";
                    });
                    table += "</tr>";
                });
                table += '<tbody></table>';
                $('.container').html(table);
                $('#myDatatable').dataTable();
            },
            dataType: "json"
        });
    });
});

PHP

$table_id = filter_input(INPUT_POST, "table_id", FILTER_SANITIZE_STRING);
$dbconn = mysqli_connect("localhost", "username", "password");

if($table_id == "table1") {
    $sql_query = mysqli_query($dbconn, 'SELECT * FROM display_branch');
}
else {
    $sql_query = mysqli_query($dbconn, 'SELECT * FROM display_marks');
}

if(mysqli_num_rows($sql_query) == 0) {
    echo "Check your ID";
    exit(1);
}
$data = array();
$data['aaData'] = array();
while($row = mysqli_fetch_assoc($sql_query)) {
    $data['aaData'][] = $row;
}

$data['aoColumns'] = array();
while($finfo = mysqli_fetch_field($sql_query)) {
    $data['aoColumns'][] = $finfo->name;
}
echo json_encode($data);

HTML

<button id="table1" class="abutton">Table 1</button><br /><button id="table2" class="abutton">Table 2</button>
<div class="container"></div>

Hope this helps.

来源：https://stackoverflow.com/questions/14098680/dynamically-get-column-names-in-acolumns-arrary-in-datatables

标签

php

json

codeigniter

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jquery-datatables