get column according to table

http://angularjs.org/

HTML

<script src="http://code.angularjs.org/angular-1.0.1.js"></script>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<div ng-controller="MyCtrl">
  Hello, {{name}}!
  
  <form class="form-inline" role="form" name="joinGeneralInfo">
  <div class="col-xs-2"> 
    <select class="form-control" style="max-height:30px;" ng-model="sourceTable"
             ng-options="tabelName.label for tabelName in operationData"
             ng-change="getOperationColumns(sourceTable)">
    <option value=""> Source Tables</option>
     <option value=""> Source Tables</option>
      <option value=""> Source Tables</option>
       <option value=""> Source Tables</option>
        <option value=""> Source Tables</option> <option value=""> Source Tables</option>
         <option value=""> Source Tables</option>
          <option value=""> Source Tables</option>
           <option value=""> Source Tables</option>
     </select>

  </div>
 
<div class="col-xs-2">
    <select class="form-control" ng-model="sourceColumn"
             ng-options="column in operationColumn">
    <option value="">Source Columns</option>
     </select>
     </div>


</form>
</div>

JavaScript

var myApp = angular.module('myApp',[]);

//myApp.directive('myDirective', function() {});
//myApp.factory('myService', function() {});

function MyCtrl($scope) {
   $scope.operationData = [
      {
             "label" : "Inventory Inventory Inventory Inventory Inventory",
             "labelType" : "Master Tables",
             "type" : "PROCESSOR",
             "outputStreams" : 1,
             "elementType" : "TABLE",
             "name" : "Inventory",
                   "columns": [
                                   {
                                  "columnName": "InvoiceName",
                                  "dataType": "varchar",
                                  "label": "Invoice Name",
                                  "required": false,
                                  "keyType":"PK"
                               },
                               {
                                  "columnName": "InvoiceDate",
                                  "dataType": "varchar",
                                  "label": "Invoice Date",
                                  "required": false
                               }
                              ]
       },{
           "label" : "Order",
           "labelType" : "OutPut Tables",
           "type" : "PROCESSOR",
           "outputStreams" : 1,
           "elementType" : "TABLE",
           "name" : "Order",
           "columns": [
                           {
                          "columnName": "OrderName",
                          "dataType": "varchar",
                          "label":  "Order Name",
                          "required": false
                       },
                       {
                          "columnName": "OrderDate",
                          "dataType": "varchar",
                          "label": "Order Date",
                          "required": false
                       }
                      ]
     },
     {
         
         "label" : "Purchase Order...