query data from a web service

sundussabbah · ‎04-23-2015

Hello everybody, I'm trying to query some data from a service table I wrote: var query = new Query(); query.outFields = [ " * " ]; query.returnGeometry = true; var queryTask = new QueryTask("url"); queryTask.execute(query,showResults); but the showResult is never executed , what is the reason ?? please help me

TomSellsted · ‎04-24-2015

Sundus,

It looks like you are just wanting to display data from the feature class table. Adding a where clause will work for this purpose. Here is an example based on a sample from the ESRI JavaScript API page. I have modified it to use your service.

ESRI Sample: Query data without a map | ArcGIS API for JavaScript

<!DOCTYPE html>
<html>


<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <!--The viewport meta tag is used to improve the presentation and behavior of the samples
      on iOS devices-->
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
    <title>Query Musanda Project Details</title>


    <script src="http://js.arcgis.com/3.13/"></script>
    <script>
        require([
            "dojo/dom", "dojo/on",
            "esri/tasks/query", "esri/tasks/QueryTask", "dojo/domReady!"
        ], function(dom, on, Query, QueryTask) {




            on(dom.byId("execute"), "click", execute);


            function execute() {
                queryTask = new QueryTask("URL to your Map Service");
                //build query filter
                query = new Query();
                query.where = "ESRI_OID > 0";
                query.returnGeometry = false;
                query.outFields = ["*"];
                query.spatialRelationship = Query.SPATIAL_REL_INTERSECTS;
                queryTask.execute(query, showResults);
            }


            function showResults(results) {
                var resultItems = [];
                var resultCount = results.features.length;
                for (var i = 0; i < resultCount; i++) {
                    var featureAttributes = results.features.attributes;
                    for (var attr in featureAttributes) {
                        resultItems.push("<b>" + attr + ":</b>  " + featureAttributes[attr] + "<br>");
                    }
                    resultItems.push("<br>");
                }
                dom.byId("info").innerHTML = resultItems.join("");
            }
        });
    </script>
</head>


<body>
    Projects:
    <input id="execute" type="button" value="Get Details">
    <br />
    <br />
    <div id="info" style="padding:5px; margin:5px; background-color:#eee;">
    </div>
</body>


</html>

I hope this helps!

Regards,

Tom

View solution in original post

sundussabbah · ‎04-23-2015

Hello everybody,

I'm trying to query some data from a service table

I wrote:

var query = new Query();

query.outFields = [ " * " ];

query.returnGeometry = true;

var queryTask = new QueryTask("url");

queryTask.execute(query,showResults);

but the showResult is never executed , what is the reason ??

please help me

TomSellsted · ‎04-23-2015

Sundus,

A more complete code listing would be helpful to diagnose your problem. It may be a poorly formed query that is not returning any results. Do you have a where clause or are you querying by an ID or spatially?

Regards,

Tom

LukePhilips · ‎04-23-2015

queryTask = new esri.tasks.QueryTask(gpURL);
        //build query filter
        query = new esri.tasks.Query();
        query.returnGeometry = false;
        query.outFields = ["*"];
        query.geometry = geometry.mapPoint;
        query.spatialRelationship = esri.tasks.Query.SPATIAL_REL_INTERSECTS;
        queryTask.execute(query, successFunction, errorFunction);

Use the error callback and see what the response objects say. Also, what are you querying? A where-clause, by geography, etc?

sundussabbah · ‎04-24-2015

thank you for replying me

I have a map service which contains a layer with one table, I want to reach the table attributes and store its values in an array in order to display them in a list.

I need all the data without specification that is why I did'nt use Where clause

I wrote an error function but it is also not executed

function successFunction(featureSet) {
go.alert('sucess','jjj');
}

function errorFunction(){
go.alert('error','tt')
}

function displayProjectList(){

queryTask = new QueryTask("url");
//build query filter
query = new Query();
query.returnGeometry = false;
query.outFields = ["*"];
query.geometry = geometry.mapPoint;
query.spatialRelationship = Query.SPATIAL_REL_INTERSECTS;
queryTask.execute(query, successFunction, errorFunction);

TomSellsted · ‎04-24-2015

Sundus,

It looks like you are just wanting to display data from the feature class table. Adding a where clause will work for this purpose. Here is an example based on a sample from the ESRI JavaScript API page. I have modified it to use your service.

ESRI Sample: Query data without a map | ArcGIS API for JavaScript

<!DOCTYPE html>
<html>


<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <!--The viewport meta tag is used to improve the presentation and behavior of the samples
      on iOS devices-->
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
    <title>Query Musanda Project Details</title>


    <script src="http://js.arcgis.com/3.13/"></script>
    <script>
        require([
            "dojo/dom", "dojo/on",
            "esri/tasks/query", "esri/tasks/QueryTask", "dojo/domReady!"
        ], function(dom, on, Query, QueryTask) {




            on(dom.byId("execute"), "click", execute);


            function execute() {
                queryTask = new QueryTask("URL to your Map Service");
                //build query filter
                query = new Query();
                query.where = "ESRI_OID > 0";
                query.returnGeometry = false;
                query.outFields = ["*"];
                query.spatialRelationship = Query.SPATIAL_REL_INTERSECTS;
                queryTask.execute(query, showResults);
            }


            function showResults(results) {
                var resultItems = [];
                var resultCount = results.features.length;
                for (var i = 0; i < resultCount; i++) {
                    var featureAttributes = results.features.attributes;
                    for (var attr in featureAttributes) {
                        resultItems.push("<b>" + attr + ":</b>  " + featureAttributes[attr] + "<br>");
                    }
                    resultItems.push("<br>");
                }
                dom.byId("info").innerHTML = resultItems.join("");
            }
        });
    </script>
</head>


<body>
    Projects:
    <input id="execute" type="button" value="Get Details">
    <br />
    <br />
    <div id="info" style="padding:5px; margin:5px; background-color:#eee;">
    </div>
</body>


</html>

I hope this helps!

Regards,

Tom

sundussabbah · ‎04-24-2015

Hi Mr .Tom

thank you for your reply, I have sent you a message of your linkedin account. please send me your feedback

could you please send me your email

Many thanks

LukePhilips · ‎04-24-2015

You still want to query something. Tom's example is good, another typical 'dummy' query to get all data is: WHERE 1=1

sundussabbah · ‎04-24-2015

thank you every body, it works well, although I still did'nt know why it did'nt execute the query, is it because I did'nt write where clause ??!!

thank you very much

TomSellsted · ‎04-25-2015

Sundus,

Yes, you must query something. You can query by IDs, by attributes or spatially. Your original post had all the parameters except what to query.

Regards,

Tom