How to initialize a WFS Layer?

Question

Here is the code block (the layers are stored in Oracle database):

var saveStrategy = new OpenLayers.Strategy.Save();

var adresspt_wfs = new OpenLayers.Layer.Vector("Address points WFS", {
     strategies: [new OpenLayers.Strategy.BBOX(), saveStrategy],
        protocol: new OpenLayers.Protocol.WFS({
        url: "http://localhost:8080/geoserver/wfs",
        featureType: "RAILWAY",
        featureNS: "http://localhost:8080/MIA",
        srsName: "EPSG:900913",
        geometryName: "SDO_GEOMETRY"
      })
    });

map.addLayer(adresspt_wfs);   

Please correct me if I'm wrong: It adds new vector layer "Address points WFS", on which we can edit/delete/add some vector objects. After save all that will be saved RAILWAY table as a geometry objects in SDO_GEOMETRY column using WFS service, that is part of GeoServer (in my case I use GeoServer)... Is that right?

Also, I don't quite understand what is "featureNS" and where to find the proper one for my layer.

If I open: http://localhost:8080/geoserver/wfs/DescribeFeatureType?version=1.1.0&typename=MIA:RAILWAY in address bar, the browser hangs on opening that schema...

MIA is my default workspace, its URI is http://localhost:8080/MIA

I've tried many configurations for initializing the WFS protocol, but can't save drawn geometry into database... Please show me what am I doing wrong during this initialization.

Please consider that I'm completely new to "geo" programming.

Answer 1

Take a look at this code example:

var adresspt_wfs = new OpenLayers.Layer.Vector("Address points WFS", {
 strategies: [new OpenLayers.Strategy.BBOX(), saveStrategy],
    protocol: new OpenLayers.Protocol.WFS({
    url: "http://localhost:8080/geoserver/wfs",
    featurePrefix: "XXXX" //<-- GeoServer workspace name
    featureType: "RAILWAY",//<-- layer name
    featureNS: "http://localhost:8080/MIA", //<-- Edit Workspace Namespace URI
    srsName: "EPSG:900913",
    geometryName: "SDO_GEOMETRY" //<-- geometry field
  })
});

The featureNS property is equivalent to your Namespace URI in the Edit Workspace page of GeoServer:

Here's a tutorial

Answer 2

As CaptDragon says it is the namespace for the features returned by the server.

As a sample if you make a request to the open server 'http://demo.opengeo.org/geoserver/wfs'

you will get a XML (a GML file) like:

<?xml version="1.0" encoding="UTF-8"?>
<wfs:FeatureCollection 
    xmlns="http://www.opengis.net/wfs" 
    xmlns:wfs="http://www.opengis.net/wfs"     
    xmlns:topp="http://www.openplans.org/topp"  <--- THIS !!!
    xmlns:gml="http://www.opengis.net/gml" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://www.openplans.org/topp 
    http://demo.opengeo.org/geoserver/wfs?service=WFS&amp;version=1.0.0&amp;request=DescribeFeatureType&amp;typeName=topp%3Astates http://www.opengis.net/wfs http://demo.opengeo.org/geoserver/schemas/wfs/1.0.0/WFS-basic.xsd">

<topp:the_geom>  <--- YOUR GEOM IS WITHIN THE topp Namespace
   <gml:MultiPolygon srsName="http://www.opengis.net/gml/srs/epsg.xml#4326">
       <gml:polygonMember><gml:Polygon><gml:outerBoundaryIs><gml:LinearRing>
          <gml:coordinates xmlns:gml="http://www.opengis.net/gml" decimal="." cs="," ts=" ">-88.071564,37.51099 -88.087883,37.476273 -88.311707,37


    <gml:boundedBy>
        <gml:Box srsName="http://www.opengis.net/gml/srs/epsg.xml#4326">       
            <gml:coordinates xmlns:gml="http://www.opengis.net/gml" decimal="." cs="," ts=" ">-124.731422,24.955967 

As you can see your the requestes features are named "topp:the_geom".