how to get the result (true or false) of an operation (create, update or delete) from the server

Hi Jose,

 Upon update, the DataSource expects the result (optionally) to contain data with the same structure as the read request one. If such data is present, the models data will be updated with the new server.

However, in your case, it seems like you are trying to validate the data sent to the server - is this so? If this is the case, the proper way to do it is to return the corresponding HTTP code (422 - unprocessable entity) if error is encountered. This would in turn trigger the DataSource error event, which you can process further.

Please let me know if this helps.  

All the best,
Petyo
the Telerik team

hi Petyo,  thanks for the reply, but I didn't understand your explanation!

Yes, I'm trying to validate the data sent to the server when I run an UPDATE operation on database. 

I'll try to be clearer. Here's the code in detail:


Kendo Script
------------------

          <script>
                $(document).ready(function() {
                    
 
                    var Item = kendo.data.Model.define({
                        id: "id_student"
                    });
                    
                    var model = null; 


      var JsonDataSource = new kendo.data.DataSource({
                        transport: {
                            read: {
                                url: "students_read.php", 
                                dataType: "JSON"
                            },
                            create: {
                                url: "students_add.php", 
                                type: "POST"
                            },
                            update: {
                                url: "students_update.php",
                                type: "POST"
                            } ,
destroy: {
                                url: "students_delete.php",
                                type: "POST"
                            }
                        },
                        schema:{
                            model: Item
                        }
                    });




                  function onChange() {
                   
    var tr = this.select();
                        var id = tr.data("id");
                        model = this.dataSource.get(id);
                   
                        $("#id").val(model.get("id_student"));         
                        $("#name").val(model.get("name"));
                                   
                    }


                 $("#grid").kendoGrid({
                        autoBind: false,
                        dataSource:JsonDataSource,
                        height: 350,
                        selectable: "row",
                        pageable: false,
                        sortable: true,
                        scrollable: true,
                        change: onChange,
                        columns: [
                                  { title : "Id", field :"id_student"},
                                  { title : "Name", field :"name"}
                                ]
                    });
                    
                    $("#btn_load").click(function() {
                        JsonDataSource.read({name: $('#search').val()});
                    });
                    
                     $("#search").keydown(function(e) {
                        if (e.keyCode === kendo.keys.ENTER) {
                            JsonDataSource.read({name: $('#search').val()});
                        }
                    });
                    
                    $("#btn_add").click(function() {
                        $('#id').val(null);
                        $('#name').val(null);
                    });
                    
                    $("#btn_save").click(function() {
                        if ($('#id').val() == ''){
                            JsonDataSource.add({ aluno: $('#name').val() });
                            JsonDataSource.sync();
                            $('#search').val($('#name').val());
                            JsonDataSource.read({name: $('#search').val()});
                        }else{
                            model.set("aluno", $('#name').val());
                            JsonDataSource.sync();
                        }
                    });
                    
                    $("#btn_delete").click(function() {
                        JsonDataSource.remove(model);
                        JsonDataSource.sync();
                    });
                
                });
            </script>


HTML tags
---------------


       <div id="example" class="k-content">
            <div>
                Search:&nbsp;&nbsp;<input id="search" name="search" />
                <button id="btn_load">Load Data</button>
            </div><br/>
            <div id="grid"></div>
            <dl>
                <dt>Student:</dt><br/>
                <dd>Id:&nbsp;&nbsp;<input id="id" name="id" readonly="readonly"/></dd><br/>
                <dd>Name:&nbsp;&nbsp;<input id="name" name="name" /></dd><br/>
                <dd><button id="btn_add">New</button>&nbsp;&nbsp;&nbsp;<button id="btn_save">Save</button>&nbsp;&nbsp;&nbsp;<button id="btn_delete">Delete</button></dd>
            </dl>
       </div>
            
PHP script (students_update.php)
--------------------------------------------
<?php


$host = "localhost";
$username = "root";
$password = "root";
$db = "school";


$id_student = $_POST["id_student"];
$name = $_POST["name"];
        
    mysql_connect($host,$username,$password);
mysql_selectdb($db);

mysql_query("UPDATE students set name = '".$name."'  WHERE id_student = '".$id_student."'");
$result = array("result" => (mysqli_affected_rows >= 0)); 

echo json_encode($result);
?>


I wonder how to implement the code(Kendo Script) above to show the result of the UPDATE operation (if there was success or failure) via an alert (). example;


if (result == true) {
  alert("Sucess Update");
}else{
  alert("Fault Update");
}


The question is: How do I do this? You could implement the code? The only thing missing to complete the example that full CRUD (Kendo + PHP) and send to the community.

<Bump>
This is something I have been battling with as well. I need to parse the response text sent back from the PHP script (I don't want to just send back an HTTP error code thanks). I could do this via jQuery .ajax() using the success() call back method, but this is not available via the Kendo datasource object (I notice it has its own internal success method). Any way round this, or do I need to ditch the datasource CRUD methods and roll my own? Cheers.

I built on top of the recommendation Petyo posted back in November.  This flow is working for us right now, although it's a bit of a work around because of the server error 422 Kendo is looking for.  Either way, I hope it can help some of you out.

Client Side Javascript:

Server Side Java Servlet:

Since our Java servlet is returning a 422 error, I needed to configure a custom error page in my web application to generate a JSON response that I could read within our KendoUI client listening for the error event.

web.xml entry

Now for the simple error422.jsp page that will create the JSON response for us.

Once again, this works for us at this point.  Hopefully someone can benefit from my research...this was a tricky one to understand.

-Brendan

This works!

You can use the datasource requestEnd function to know the status of the response.

requestEnd: function(e) {
                    var response = e.response;
                    var type = e.type;
                    if (type == "undefined") {
                        showError();
                    }
                    else {
                        showSuccess(type);
                    }
},