OK tried it in fiddle. You can have a non numeric data-identifier. (IMHO it should be called data-row-identifier...)
In order to access that column you simply use the name you set in the data-column-identifier, so:
<!-- works!! even without data-type="numeric" -->
<th data-column-id="myid" data-identifier="true">My ID</th>
<th data-column-id="info">Info</th>
</tr>
</thead>
and the code should be
$("#mygrid").bootgrid(
{
// other settings... and:
selection: true
}).on("selected.rs.jquery.bootgrid", function(e, rows)
{
alert("Selected: " + rows[0].myid);
});
Here's a jsfiddle to prove the point