function login(email, password, callback) {
      //this example uses the "tedious" library
      //more info here: http://pekim.github.io/tedious/index.html
      var Connection = require('tedious@1.11.0').Connection;
      var Request = require('tedious@1.11.0').Request;
      var TYPES = require('tedious@1.11.0').TYPES;

      var connection = new Connection({
        userName: 'username',
        password: 'pass',
        server: 'server',
        options: {
          database: 'db',
          encrypt: true,
          rowCollectionOnRequestCompletion: true
        }
      });

      var query = "SELECT Id, Email, Password " +
        "FROM user WHERE Email = @Email";

      connection.on('debug', function (text) {
        // Uncomment next line in order to enable debugging messages
        // console.log(text);
      }).on('errorMessage', function (text) {
        console.log(JSON.stringify(text, null, 2));
        return callback(text);
      }).on('infoMessage', function (text) {
        // Uncomment next line in order to enable information messages
        // console.log(JSON.stringify(text, null, 2));
      });

      connection.on('connect', function (err) {
        if (err) { return callback(err); }

        var request = new Request(query, function (err, rowCount, rows) {
          if (err) {
            callback(new Error(err));
          } else if (rowCount < 1) {
            callback(new WrongUsernameOrPasswordError(email));
          } else {
            bcrypt.compare(password, rows[0][2].value, function (err, isValid) {
              if (err) { callback(new Error(err)); }
              else if (!isValid) { callback(new WrongUsernameOrPasswordError(email)); }
              else {
                callback(null, {
                  user_id: rows[0][0].value,
                  email: rows[0][1].value
                });
              }
            });
          }
        });

        request.addParameter('Email', TYPES.VarChar, email);
        connection.execSql(request);
      });
    }