I'm having some troubles with SQLiteCopy

Hello all, first i’m a newbie, I’m having some issues in copying SQLite database ( or maybe read it ), i’ve already tried a lots of codes but without any result, all what i want is to do a login page that verify user/password, at first i want to verify the connection, i used some alerts to ensure that, but no one of them show, please i need your help,
sometime i got an error that says " TypeError: Cannot read property ‘transaction’ of null "
i’d installed :

  • sqlite
  • cordova-plugin-dbcopy
  • and ng-cordova.min.js

i’ve tried many methodes that i found in the Internet but no one works for me
(sorry for my English guys)

app.js
`

db = null;
angular.module('starter', ['ionic', 'ngCordova', 'starter.controllers', 'starter.services'])

.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 !== undefined) {

            // copy the database
            window.plugins.sqlDB.copy("utilisateurs.db", 1,

            function () {
                // copy success, if not yet been copied
                // set "db" as the database
                db = window.sqlitePlugin.openDatabase({ name: "utilisateurs.db", location: 2, createFromLocation: 1 });
                alert("SUCCES");
            }, function () {
                // copy error, if it has already been copied
                // set "db" as the database
                db = window.openDatabase("utilisateurs.db", "1.0", "Database", 200000);
                alert("ERROR");
            });
        } else {
            alert("not loaded");
        } 
    });
})`

controllers.js

.controller('ngController', function ($scope) {

    $scope.selectAll = function () {
        // db is your database defined before
        db.transaction(function (tx) {
            // running a sql querie 
            tx.executeSql("SELECT id, utilisateur FROM utilisateurs", [], 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).id + ' ' + res.rows.item(i).utilisateur); // showing the results
                }
            }, function (e) {
                alert("ERROR: " + e.message);
            });
        });
    };

})