Problem at Transaction or sqlite ?,

someone help me please, i dont know where is the problem with my code , i got an error message from transaction function ( i know that from the alert that i defined inside it)

app.js

// global variable where will define the database
var db = null;

angular.module('starter', ['ionic', 'ngCordova'])

.run(function($ionicPlatform, $cordovaSQLite) {
  $ionicPlatform.ready(function() {
    if (window.cordova && window.cordova.plugins.Keyboard) {
      cordova.plugins.Keyboard.hideKeyboardAccessoryBar(true);
    }
    if (window.StatusBar) {
      StatusBar.styleDefault();
    }

        /* DATABASE INTEGRATION */   

  if (window.sqlitePlugin) {

    // copy the database
    window.plugins.sqlDB.copy("utilisateurs.db",

    function () {
      // copy success, if not yet been copied
      // set "db" as the database
      db = window.sqlitePlugin.openDatabase({name: "utilisateurs.db"});
      alert("copysuccess");
    }, function() {
      // copy error, if it has already been copied
      // set "db" as the database
      db = window.sqlitePlugin.openDatabase({name: "utilisateurs.db"});
      alert("copyerror");
    });
  } else {
        db = window.openDatabase("utilisateurs.db", "1.0", "utilisateurs.db", 200000);
        alert("copy browser");
    }
  });
})

.controller('ExampleCtrl', function($scope) {
  
  $scope.order = function(){
                // db is your database defined before
    console.log("start order ");
    db.transaction(function(tx) {
                        // running a sql querie 
      tx.executeSql("SELECT username, password FROM users", [], function(tx, res) {
        var len = res.rows.length;
        for (var i = 0; i < len; i++) { // loop as many times as there are row results
          alert( res.rows.item(i).username +' '+ res.rows.item(i).password ); // showing the results
        }
      }, function(e) {
        console.log("error trans " + e);
        alert("ERROR: " + e.message);
      });
    });
  };
  
})

index.html

 <!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no, width=device-width">
    <title></title>

    <link href="lib/ionic/css/ionic.css" rel="stylesheet">
    <link href="css/style.css" rel="stylesheet">

    <!-- IF using Sass (run gulp sass first), then uncomment below and remove the CSS includes above
    <link href="css/ionic.app.css" rel="stylesheet">
    -->

    <!-- ionic/angularjs js -->
    <script src="lib/ionic/js/ionic.bundle.js"></script>

    <!-- cordova script (this will be a 404 during development) -->

    <script src="js/ng-cordova.min.js"></script>
    <script src="cordova.js"></script>

    <!-- your app's js -->
    <script src="js/app.js"></script>
  </head>
  <body ng-app="starter">

    <ion-pane>
      <ion-header-bar class="bar-stable">
        <h1 class="title">Ionic Blank Starter</h1>
      </ion-header-bar>
      <ion-content ng-controller="ExampleCtrl">
      <button class="button" ng-click="order()"></button>
      </ion-content>
    </ion-pane>
  </body>
</html>