columns data vs. sInt & sName

Following is an excerpt:
If I use data, then data are not shown in the table. But if I changed data to sInt & sName, data are shown in the table.
Why is that?

$('#example').DataTable( {

    dom: 'Bfrtip',
type: 'POST',
    bServerSide: true,
    sAjaxSource: "folder/myServlet",
    bProcessing: true,
    spagingType: 'full_numbers',
    bJQueryUI: true,
    select: true,

    columns: [
    { "sInt": "id",
                "bSearchable": false,
                "bSortable": false,
                "bVisible": false  },
        { "sName": "payerID" },
        { "sName": "payerName" },
        { "sName": "contractID" },
        { "sName": "insCo" },
        { "sName": "insType" },
        { "sName": "groupID" },
        { "sName": "eff" },
        { "sName": "term" }

    ],

/* another version with data
{ data: "id",
"bSearchable": false,
"bSortable": false,
"bVisible": false },
{ data: "payerID" },
{ data: "payerName" },
{ data: "contractID" },
{ data: "insCo" },
{ data: "insType" },
{ data: "groupID" },
{ data: "eff" },
{ data: "term" }
*/

Thanks