diff --git a/Dockerfile b/Dockerfile
index 11bd6fd8..d2e547ee 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,7 +10,7 @@ RUN sed -i '/security.debian.org/d' /etc/apt/sources.list \
 RUN echo "deb http://archive.debian.org/debian/ stretch main" > /etc/apt/sources.list \
     && echo "deb http://archive.debian.org/debian-security stretch/updates main" >> /etc/apt/sources.list
 
-RUN apt-get update && apt-get install -y zlib1g-dev libicu-dev g++ wget git
+RUN apt-get update && apt-get install -y zlib1g-dev libicu-dev g++ wget git zip
 
 RUN wget --no-check-certificate https://pecl.php.net/get/xdebug-2.5.5.tgz \
     && pecl install --offline ./xdebug-2.5.5.tgz \
diff --git a/actions-sms.php b/actions-sms.php
index 5f1e5726..832c7464 100644
--- a/actions-sms.php
+++ b/actions-sms.php
@@ -1,4 +1,9 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("common.php");
 
 function help($number)
@@ -320,7 +325,7 @@ function returnBike($number,$bike,$stand,$message="",$force=FALSE)
       {
       $userNote="";
       }
-   else $userNote=$db->conn->real_escape_string(trim($matches[1]));
+   else $userNote=$db->escape(trim($matches[1]));
 
    $result=$db->query("UPDATE bikes SET currentUser=NULL,currentStand=$standId WHERE bikeNum=$bikeNum");
    if ($userNote)
@@ -509,28 +514,30 @@ function freeBikes($number)
 
 function log_sms($sms_uuid, $sender, $receive_time, $sms_text, $ip)
 {
-   global $dbserver,$dbuser,$dbpassword,$dbname;
-        $localdb=new Database($dbserver,$dbuser,$dbpassword,$dbname);
-        $localdb->connect();
-        $localdb->conn->autocommit(TRUE);
-
-   $sms_uuid =$localdb->conn->real_escape_string($sms_uuid);
-   $sender =$localdb->conn->real_escape_string($sender);
-   $receive_time =$localdb->conn->real_escape_string($receive_time);
-   $sms_text =$localdb->conn->real_escape_string($sms_text);
-   $ip =$localdb->conn->real_escape_string($ip);
-
-        $result =$localdb->query("SELECT sms_uuid FROM received WHERE sms_uuid='$sms_uuid'");
-        if (DEBUG===FALSE AND $result->num_rows>=1) // sms already exists in DB, possible problem
-           {
-           notifyAdmins(_('Problem with SMS')." $sms_uuid!",1);
-           return FALSE;
-           }
-        else
-           {
-           $result =$localdb->query("INSERT INTO received SET sms_uuid='$sms_uuid',sender='$sender',receive_time='$receive_time',sms_text='$sms_text',ip='$ip'");
-           }
-
+    global $dbserver, $dbuser, $dbpassword, $dbname;
+    /**
+     * @var DbInterface
+     */
+    $localdb = new MysqliDb($dbserver, $dbuser, $dbpassword, $dbname);
+    $localdb->connect();
+
+    #TODO does it needed???
+    $localdb->setAutocommit(true);
+
+    $sms_uuid = $localdb->escape($sms_uuid);
+    $sender = $localdb->escape($sender);
+    $receive_time = $localdb->escape($receive_time);
+    $sms_text = $localdb->escape($sms_text);
+    $ip = $localdb->escape($ip);
+
+    $result = $localdb->query("SELECT sms_uuid FROM received WHERE sms_uuid='$sms_uuid'");
+    if (DEBUG === FALSE and $result->num_rows >= 1) {
+        // sms already exists in DB, possible problem
+        notifyAdmins(_('Problem with SMS') . " $sms_uuid!", 1);
+        return FALSE;
+    } else {
+        $result = $localdb->query("INSERT INTO received SET sms_uuid='$sms_uuid',sender='$sender',receive_time='$receive_time',sms_text='$sms_text',ip='$ip'");
+    }
 }
 
 
@@ -554,7 +561,7 @@ function delnote($number,$bikeNum,$message)
 	}
 	else
 	{
-      	sendSMS($number,_('Error in bike number / stand name specification:'.$db->conn->real_escape_string($bikeNum)));
+      	sendSMS($number,_('Error in bike number / stand name specification:'.$db->escape($bikeNum)));
 		return;
 	}
 	   
@@ -587,7 +594,7 @@ function delnote($number,$bikeNum,$message)
    $reportedBy=$row["userName"];
 
       $matches=explode(" ",$message,3);
-      $userNote=$db->conn->real_escape_string(trim($matches[2]));
+      $userNote=$db->escape(trim($matches[2]));
 
 	if($userNote=='')
 	{
@@ -595,7 +602,7 @@ function delnote($number,$bikeNum,$message)
 	}
 
       $result=$db->query("UPDATE notes SET deleted=NOW() where bikeNum=$bikeNum and deleted is null and note like '%$userNote%'");
-      $count = $db->conn->affected_rows;
+      $count = $db->getAffectedRows();
 
 	if($count == 0)
 	{
@@ -647,7 +654,7 @@ function untag($number,$standName,$message)
 
 
       $matches=explode(" ",$message,3);
-      $userNote=$db->conn->real_escape_string(trim($matches[2]));
+      $userNote=$db->escape(trim($matches[2]));
 
 	if($userNote=='')
 	{
@@ -655,7 +662,7 @@ function untag($number,$standName,$message)
 	}
 
     $result=$db->query("update notes join bikes on notes.bikeNum = bikes.bikeNum set deleted=now() where bikes.currentStand='$standId' and note like '%$userNote%' and deleted is null");
-    $count = $db->conn->affected_rows;
+    $count = $db->getAffectedRows();
 
 	if($count == 0)
 	{
@@ -706,7 +713,7 @@ function delstandnote($number,$standName,$message)
 
 
       $matches=explode(" ",$message,3);
-      $userNote=$db->conn->real_escape_string(trim($matches[2]));
+      $userNote=$db->escape(trim($matches[2]));
 
 	if($userNote=='')
 	{
@@ -714,7 +721,7 @@ function delstandnote($number,$standName,$message)
 	}
 
       $result=$db->query("UPDATE notes SET deleted=NOW() where standId=$standId and deleted is null and note like '%$userNote%'");
-      $count = $db->conn->affected_rows;
+      $count = $db->getAffectedRows();
 
 	if($count == 0)
 	{
@@ -765,7 +772,7 @@ function standNote($number,$standName,$message)
 
 
     $matches=explode(" ",$message,3);
-    $userNote=$db->conn->real_escape_string(trim($matches[2]));
+    $userNote=$db->escape(trim($matches[2]));
 
    if ($userNote=="") //deletemmm
       {
@@ -781,7 +788,7 @@ function standNote($number,$standName,$message)
    else
       {
       $db->query("INSERT INTO notes SET standId='$standId',userId='$userId',note='$userNote'");
-      $noteid=$db->conn->insert_id;
+      $noteid=$db->getLastInsertId();
       sendSMS($number,_('Note for stand')." ".$standName." "._('saved').".");
       notifyAdmins(_('Note #').$noteid.": "._("on stand")." ".$standName." "._('by')." ".$reportedBy." (".$number."):".$userNote);
       }
@@ -813,7 +820,7 @@ function tag($number,$standName,$message)
 
 
     $matches=explode(" ",$message,3);
-    $userNote=$db->conn->real_escape_string(trim($matches[2]));
+    $userNote=$db->escape(trim($matches[2]));
 
    if ($userNote=="") //deletemmm
       {
@@ -829,7 +836,7 @@ function tag($number,$standName,$message)
    else
       {
       $db->query("INSERT INTO notes (bikeNum,userId,note) SELECT bikeNum,'$userId','$userNote' FROM bikes where currentStand='$standId'");
-      //$noteid=$db->conn->insert_id;
+      //$noteid=$db->getLastInsertId();
       sendSMS($number,_('All bikes on stand')." ".$standName." "._('tagged').".");
       notifyAdmins(_('All bikes on stand')." "."$standName".' '._('tagged by')." ".$reportedBy." (".$number.")". _("with note:").$userNote);
       }
@@ -855,7 +862,7 @@ function note($number,$bikeNum,$message)
 	}
 	else
 	{
-      	sendSMS($number,_('Error in bike number / stand name specification:'.$db->conn->real_escape_string($bikeNum)));
+      	sendSMS($number,_('Error in bike number / stand name specification:'.$db->escape($bikeNum)));
 		return;
 	}
 	   
@@ -892,7 +899,7 @@ function note($number,$bikeNum,$message)
    else
       {
       $matches=explode(" ",$message,3);
-      $userNote=$db->conn->real_escape_string(trim($matches[2]));
+      $userNote=$db->escape(trim($matches[2]));
       }
 
    if ($userNote=="")
@@ -911,7 +918,7 @@ function note($number,$bikeNum,$message)
    else
       {
       $db->query("INSERT INTO notes SET bikeNum='$bikeNum',userId='$userId',note='$userNote'");
-      $noteid=$db->conn->insert_id;
+      $noteid=$db->getLastInsertId();
       sendSMS($number,_('Note for bike')." ".$bikeNum." "._('saved').".");
       notifyAdmins(_('Note #').$noteid.": b.".$bikeNum." (".$bikeStatus.") "._('by')." ".$reportedBy." (".$number."):".$userNote);
       }
@@ -1028,8 +1035,8 @@ function add($number,$email,$phone,$message)
       sendSMS($number,_('Contact information is in incorrect format. Use:')." ADD king@earth.com 0901456789 Martin Luther King Jr.");
       return;
    }
-   $userName=$db->conn->real_escape_string(trim($matches[2]));
-   $email=$db->conn->real_escape_string(trim($matches[1]));
+   $userName=$db->escape(trim($matches[2]));
+   $email=$db->escape(trim($matches[1]));
 
    $result=$db->query("INSERT into users SET userName='$userName',number=$phone,mail='$email'");
 
diff --git a/admin.php b/admin.php
index 821c15e3..819726b7 100644
--- a/admin.php
+++ b/admin.php
@@ -1,15 +1,22 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
 require('actions-web.php');
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 
 checksession();
 
 if (isset($_COOKIE["loguserid"])) {
-    $userid = $db->conn->real_escape_string(trim($_COOKIE["loguserid"]));
+    $userid = $db->escape(trim($_COOKIE["loguserid"]));
 } else {
     $userid = 0;
 }
diff --git a/agree.php b/agree.php
index e22bdd4a..463f91cc 100644
--- a/agree.php
+++ b/agree.php
@@ -1,9 +1,16 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
 require('actions-web.php');
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 ?>
 <!DOCTYPE html>
diff --git a/command.php b/command.php
index 11e7c655..0d954e4d 100644
--- a/command.php
+++ b/command.php
@@ -1,19 +1,26 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
 require('actions-web.php');
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 
 if (isset($_COOKIE["loguserid"])) {
-    $userid = $db->conn->real_escape_string(trim($_COOKIE["loguserid"]));
+    $userid = $db->escape(trim($_COOKIE["loguserid"]));
 } else {
     $userid = 0;
 }
 
 if (isset($_COOKIE["logsession"])) {
-    $session = $db->conn->real_escape_string(trim($_COOKIE["logsession"]));
+    $session = $db->escape(trim($_COOKIE["logsession"]));
 } else {
     $session = '';
 }
diff --git a/common.php b/common.php
index 3031e7bb..c0288143 100644
--- a/common.php
+++ b/common.php
@@ -3,6 +3,8 @@
 use BikeShare\Mail\DebugMailSender;
 use BikeShare\Mail\MailSenderInterface;
 use BikeShare\Mail\PHPMailerMailSender;
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
 use BikeShare\SmsConnector\SmsConnectorFactory;
 
 require_once 'vendor/autoload.php';
@@ -37,7 +39,7 @@
 function error($message)
 {
    global $db;
-   $db->conn->rollback();
+   $db->rollback();
    exit($message);
 }
 
@@ -73,14 +75,19 @@ function sendSMS($number,$text)
 
 function logSendsms($number, $text)
 {
-        global $dbserver,$dbuser,$dbpassword,$dbname;
-        $localdb=new Database($dbserver,$dbuser,$dbpassword,$dbname);
-        $localdb->connect();
-        $localdb->conn->autocommit(TRUE);
-        $number = $localdb->conn->real_escape_string($number);
-        $text = $localdb->conn->real_escape_string($text);
+    global $dbserver, $dbuser, $dbpassword, $dbname;
+    /**
+     * @var DbInterface
+     */
+    $localdb = new MysqliDb($dbserver, $dbuser, $dbpassword, $dbname);
+    $localdb->connect();
 
-        $result = $localdb->query("INSERT INTO sent SET number='$number',text='$text'");
+    #TODO does it needed???
+    $localdb->setAutocommit(true);
+    $number = $localdb->escape($number);
+    $text = $localdb->escape($text);
+
+    $result = $localdb->query("INSERT INTO sent SET number='$number',text='$text'");
 
 }
 
@@ -165,8 +172,8 @@ function isloggedin()
 {
     global $db;
     if (isset($_COOKIE['loguserid']) and isset($_COOKIE['logsession'])) {
-        $userid = $db->conn->real_escape_string(trim($_COOKIE['loguserid']));
-        $session = $db->conn->real_escape_string(trim($_COOKIE['logsession']));
+        $userid = $db->escape(trim($_COOKIE['loguserid']));
+        $session = $db->escape(trim($_COOKIE['logsession']));
         $result = $db->query("SELECT sessionId FROM sessions WHERE userId='$userid' AND sessionId='$session' AND timeStamp>'" . time() . "'");
         if ($result->num_rows == 1) {
             return 1;
@@ -183,16 +190,16 @@ function checksession()
 
     $result = $db->query("DELETE FROM sessions WHERE timeStamp<='" . time() . "'");
     if (isset($_COOKIE['loguserid']) and isset($_COOKIE['logsession'])) {
-        $userid = $db->conn->real_escape_string(trim($_COOKIE['loguserid']));
-        $session = $db->conn->real_escape_string(trim($_COOKIE['logsession']));
+        $userid = $db->escape(trim($_COOKIE['loguserid']));
+        $session = $db->escape(trim($_COOKIE['logsession']));
         $result = $db->query("SELECT sessionId FROM sessions WHERE userId='$userid' AND sessionId='$session' AND timeStamp>'" . time() . "'");
         if ($result->num_rows == 1) {
             $timestamp = time() + 86400 * 14;
             $result = $db->query("UPDATE sessions SET timeStamp='$timestamp' WHERE userId='$userid' AND sessionId='$session'");
-            $db->conn->commit();
+            $db->commit();
         } else {
             $result = $db->query("DELETE FROM sessions WHERE userId='$userid' OR sessionId='$session'");
-            $db->conn->commit();
+            $db->commit();
             setcookie('loguserid', '', time() - 86400);
             setcookie('logsession', '', time() - 86400);
             header('HTTP/1.1 302 Found');
@@ -210,10 +217,15 @@ function checksession()
 
 function logrequest($userid)
 {
-    global $dbserver, $dbuser, $dbpassword, $dbname;
-    $localdb = new Database($dbserver, $dbuser, $dbpassword, $dbname);
+   global $dbserver,$dbuser,$dbpassword,$dbname;
+    /**
+     * @var DbInterface
+     */
+    $localdb = new MysqliDb($dbserver, $dbuser, $dbpassword, $dbname);
     $localdb->connect();
-    $localdb->conn->autocommit(true);
+
+    #TODO does it needed???
+    $localdb->setAutocommit(true);
 
     $number = getphonenumber($userid);
 
@@ -224,20 +236,29 @@ function logresult($userid, $text)
 {
     global $dbserver, $dbuser, $dbpassword, $dbname;
 
-    $localdb = new Database($dbserver, $dbuser, $dbpassword, $dbname);
+    /**
+     * @var DbInterface
+     */
+    $localdb = new MysqliDb($dbserver, $dbuser, $dbpassword, $dbname);
     $localdb->connect();
-    $localdb->conn->autocommit(true);
-    $userid = $localdb->conn->real_escape_string($userid);
-    $logtext = '';
-    if (is_array($text)) {
-        foreach ($text as $value) {
-            $logtext .= $value . '; ';
-        }
-    } else {
-        $logtext = $text;
-    }
 
-    $logtext = strip_tags($localdb->conn->real_escape_string($logtext));
+    #TODO does it needed???
+    $localdb->setAutocommit(true);
+   $userid = $localdb->escape($userid);
+   $logtext="";
+   if (is_array($text))
+      {
+      foreach ($text as $value)
+         {
+         $logtext.=$value."; ";
+         }
+      }
+   else
+      {
+      $logtext=$text;
+      }
+
+    $logtext = strip_tags($localdb->escape($logtext));
 
     $result = $localdb->query("INSERT INTO sent SET number='$userid',text='$logtext'");
 }
@@ -312,7 +333,7 @@ function sendConfirmationEmail($emailto)
 function confirmUser($userKey)
 {
     global $db, $limits;
-    $userKey = $db->conn->real_escape_string($userKey);
+    $userKey = $db->escape($userKey);
 
     $result = $db->query("SELECT userId FROM registration WHERE userKey='$userKey'");
     if ($result->num_rows == 1) {
diff --git a/cron.php b/cron.php
index 5c4d482d..e123fa7a 100644
--- a/cron.php
+++ b/cron.php
@@ -1,9 +1,16 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
 require("actions-web.php");
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 
 checklongrental();
diff --git a/db.class.php b/db.class.php
deleted file mode 100644
index 8ec534f8..00000000
--- a/db.class.php
+++ /dev/null
@@ -1,37 +0,0 @@
-<?php
-
-class Database
-   {
-
-   function __construct($dbserver,$dbuser,$dbpassword,$dbname)
-      {
-      $this->dbserver=$dbserver;
-      $this->dbuser=$dbuser;
-      $this->dbpassword=$dbpassword;
-      $this->dbname=$dbname;
-      }
-
-   function connect()
-      {
-      $this->conn=new mysqli($this->dbserver,$this->dbuser,$this->dbpassword,$this->dbname);
-      $this->conn->set_charset("utf8");
-      $this->conn->autocommit(FALSE);
-      if (!$this->conn OR $this->conn->connect_errno) error(_('DB connection error!'));
-      return $this->conn;
-      }
-
-   function query($query)
-      {
-      $result=$this->conn->query($query);
-      if (!$result) error(_('DB error').' '.$this->conn->error.' '._('in').': '.$query);
-      return $result;
-      }
-
-   function insertid()
-      {
-      return $this->conn->insert_id;
-      }
-
-}
-
-?>
\ No newline at end of file
diff --git a/index.php b/index.php
index 28cac9f0..caae893b 100644
--- a/index.php
+++ b/index.php
@@ -1,11 +1,16 @@
 <?php
 
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
 require_once 'vendor/autoload.php';
 require "config.php";
-require "db.class.php";
 require "actions-web.php";
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 ?>
 <!DOCTYPE html>
@@ -43,7 +48,7 @@
 var mapzoom=<?php echo $systemzoom; ?>;
 <?php
 if (isset($_COOKIE["loguserid"])) {
-    $userid = $db->conn->real_escape_string(trim($_COOKIE["loguserid"]));
+    $userid = $db->escape(trim($_COOKIE["loguserid"]));
 } else {
     $userid = 0;
 }
diff --git a/install/generate.php b/install/generate.php
index 5623e4f2..8ff5e624 100644
--- a/install/generate.php
+++ b/install/generate.php
@@ -1,14 +1,19 @@
 <?php
 
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
 require_once '../vendor/autoload.php';
 if (file_exists("../config.php")) {
     require "../config.php";
 } else {
     require "../config.php.example";
 }
-require "../db.class.php";
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 
 // create new PDF document
diff --git a/install/index.php b/install/index.php
index ee816828..e853737e 100644
--- a/install/index.php
+++ b/install/index.php
@@ -1,6 +1,9 @@
 <?php
 //@TODO ANaLYTICS!!!
 
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
 if (file_exists("../config.php")) {
     exit("Project already installed. If you want to reinstall, please remove config.php file.");
 }
@@ -8,7 +11,6 @@
 require_once '../vendor/autoload.php';
 $configfilename = "../config.php.example";
 require $configfilename;
-require "../db.class.php";
 
 function changeconfigvalue($configvar,$postvar)
 {
@@ -205,7 +207,10 @@ function return_bytes($val) {
 else changeconfigvalue('countrycode',"");
 $newconfig=implode($configfile);
 file_put_contents($configfilename,$newconfig);
-$db=new Database($_POST["dbserver"],$_POST["dbuser"],$_POST["dbpassword"],$_POST["dbname"]);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($_POST["dbserver"],$_POST["dbuser"],$_POST["dbpassword"],$_POST["dbname"]);
 $db->connect();
 $sql=file_get_contents("../docker-data/mysql/create-database.sql");
 $sql=explode(";",$sql);
@@ -233,16 +238,19 @@ function return_bytes($val) {
          </form>
 <?php endif; ?>
 <?php if ($step==3):
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 $result=$db->query("REPLACE INTO users SET userName='".$_POST["username"]."',password=SHA2('".$_POST["password"]."',512),mail='".$_POST["email"]."',number='".$_POST["phone"]."',privileges=7");
-$userid=$db->conn->insert_id;
+$userid=$db->getLastInsertId();
 if (!$connectors["sms"])
    {
    $result=$db->query("UPDATE users SET number='$userid' WHERE userId='$userid'");
    }
 $result=$db->query("REPLACE INTO limits SET userId='$userid',userLimit='100'");
-$db->conn->commit();
+$db->commit();
 ?>
       <h2><?php echo _('Create bicycles and stands'); ?></h2>
        <?php echo '<div class="alert alert-success" role="alert">',_('Admin user'),' ',$_POST["username"],' ',_('created with password:'),' ',$_POST["password"]; if (!$connectors["sms"]) { echo '. ',_('Use number'),' <span class="label label-default">',$userid,'</span> ',_('for login'),'.'; } echo '</div>'; ?>
@@ -254,7 +262,10 @@ function return_bytes($val) {
 
 <?php endif; ?>
 <?php if ($step==4):
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 $stands=explode(",",$_POST["stands"]);
 foreach ($stands as $stand)
@@ -267,7 +278,7 @@ function return_bytes($val) {
    $code=sprintf("%04d",rand(100,9900)); //do not create a code with more than one leading zero or more than two leading 9s (kind of unusual/unsafe).
    $result=$db->query("REPLACE INTO bikes SET bikeNum='".$i."',currentStand=1,currentCode='".$code."'");
    }
-$db->conn->commit();
+$db->commit();
 ?>
       <h2><?php echo _('Set up stands'); ?></h2>
 <?php
@@ -317,7 +328,10 @@ function return_bytes($val) {
          </form>
 <?php endif; ?>
 <?php if ($step==5):
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 ?>
       <h2>Set system options</h2>
@@ -333,7 +347,7 @@ function return_bytes($val) {
       }
    if (isset($_POST["placename"][$standid])) $result=$db->query("UPDATE stands SET placeName='".$_POST["placename"][$standid]."' WHERE standId='$standid'");
    }
-$db->conn->commit();
+$db->commit();
 echo '<div class="alert alert-success" role="alert">',sprintf(ngettext('%d stand','%d stands',count($_POST["standdesc"])),count($_POST["standdesc"])),' ',_('set up and'),' ',sprintf(ngettext('%d photo','%d photos',$uploadtotal),$uploadtotal),' ',_('uploaded'),'</div>';
 ?>
       <form class="container" method="post" action="index.php?step=6">
@@ -386,7 +400,10 @@ function return_bytes($val) {
          </form>
 <?php endif; ?>
 <?php if ($step==6):
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 $configfile=file($configfilename);
 foreach ($_POST as $variable=>$value)
@@ -413,7 +430,7 @@ function return_bytes($val) {
    $row=$result->fetch_assoc();
    $result=$db->query("REPLACE INTO credit SET userId='".$row["userId"]."',credit='$newcredit'");
    }
-$db->conn->commit();
+$db->commit();
 ?>
       <h2>Installation finished</h2>
       <div class="alert alert-success" role="alert"><?php echo _('System options set.'); ?></div>
diff --git a/receive.php b/receive.php
index fde61b74..14830cb8 100644
--- a/receive.php
+++ b/receive.php
@@ -1,12 +1,18 @@
 <?php
 
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
 use BikeShare\SmsConnector\SmsConnectorInterface;
 
 require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
+
 require("actions-sms.php");
 
 /**
@@ -112,7 +118,7 @@
       }
    }
 
-$db->conn->commit();
+$db->commit();
 $sms->respond();
 
 ?>
\ No newline at end of file
diff --git a/scan.php b/scan.php
index 20f39192..489987ad 100644
--- a/scan.php
+++ b/scan.php
@@ -1,19 +1,26 @@
 <?php
+
+use BikeShare\Db\DbInterface;
+use BikeShare\Db\MysqliDb;
+
+require_once 'vendor/autoload.php';
 require("config.php");
-require("db.class.php");
 require('actions-qrcode.php');
 
-$db=new Database($dbserver,$dbuser,$dbpassword,$dbname);
+/**
+ * @var DbInterface
+ */
+$db=new MysqliDb($dbserver,$dbuser,$dbpassword,$dbname);
 $db->connect();
 
 if (isset($_COOKIE["loguserid"])) {
-    $userid = $db->conn->real_escape_string(trim($_COOKIE["loguserid"]));
+    $userid = $db->escape(trim($_COOKIE["loguserid"]));
 } else {
     $userid = 0;
 }
 
 if (isset($_COOKIE["logsession"])) {
-    $session = $db->conn->real_escape_string(trim($_COOKIE["logsession"]));
+    $session = $db->escape(trim($_COOKIE["logsession"]));
 } else {
     $session = '';
 }
diff --git a/src/Db/DbInterface.php b/src/Db/DbInterface.php
new file mode 100644
index 00000000..292fba40
--- /dev/null
+++ b/src/Db/DbInterface.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace BikeShare\Db;
+
+interface DbInterface
+{
+    public function connect();
+
+    /**
+     * @param string $query
+     * @param array $params
+     * @return mixed
+     */
+    public function query($query, $params = array());
+
+    /**
+     * @param $string
+     * @return string
+     */
+    public function escape($string);
+
+    /**
+     * @return int
+     */
+    public function getAffectedRows();
+
+    /**
+     * @return int
+     */
+    public function getLastInsertId();
+
+    /**
+     * TODO does it needed???
+     * @param bool $mode
+     * @return bool
+     */
+    public function setAutocommit($mode = true);
+
+    /**
+     * TODO does it needed???
+     * @return bool
+     */
+    public function commit();
+
+    /**
+     * TODO does it needed???
+     * @return bool
+     */
+    public function rollback();
+}
diff --git a/src/Db/MysqliDb.php b/src/Db/MysqliDb.php
new file mode 100644
index 00000000..2f9a5fb3
--- /dev/null
+++ b/src/Db/MysqliDb.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace BikeShare\Db;
+
+class MysqliDb implements DbInterface
+{
+    /**
+     * @var \mysqli
+     */
+    private $conn;
+    /**
+     * @var string
+     */
+    private $dbserver;
+    /**
+     * @var string
+     */
+    private $dbuser;
+    /**
+     * @var string
+     */
+    private $dbpassword;
+    /**
+     * @var string
+     */
+    private $dbname;
+    /**
+     * @var false
+     */
+    private $throwException;
+
+    public function __construct($dbserver, $dbuser, $dbpassword, $dbname, $throwException = false)
+    {
+        $this->dbserver = $dbserver;
+        $this->dbuser = $dbuser;
+        $this->dbpassword = $dbpassword;
+        $this->dbname = $dbname;
+        $this->throwException = $throwException;
+    }
+
+    public function connect()
+    {
+        $this->conn = new \mysqli($this->dbserver, $this->dbuser, $this->dbpassword, $this->dbname);
+        if (!$this->conn || $this->conn->connect_errno) {
+            if ($this->throwException) {
+                throw new \RuntimeException(
+                    'DB connection error!',
+                    !empty($this->conn->connect_errno) ? $this->conn->connect_errno : 0
+                );
+            } else {
+                die(_('DB connection error!'));
+            }
+        }
+        $this->conn->set_charset("utf8");
+        $this->conn->autocommit(false);
+    }
+
+    public function query($query, $params = array())
+    {
+        $result = $this->conn->query($query);
+        if (!$result) {
+            $this->conn->rollback();
+            if ($this->throwException) {
+                throw new \RuntimeException('DB error in : ' . $query);
+            } else {
+                die(_('DB error') . ' ' . $this->conn->error . ' ' . _('in') . ': ' . $query);
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * @return int
+     */
+    public function getAffectedRows()
+    {
+        return $this->conn->affected_rows;
+    }
+
+    public function getLastInsertId()
+    {
+        return (int)$this->conn->insert_id;
+    }
+
+    public function escape($string)
+    {
+        return $this->conn->real_escape_string($string);
+    }
+
+    /**
+     * TODO does it needed???
+     * @param bool $mode
+     * @return bool
+     */
+    public function setAutocommit($mode = true)
+    {
+        return $this->conn->autocommit($mode);
+    }
+
+    /**
+     * TODO does it needed???
+     * @return bool
+     */
+    public function commit()
+    {
+        return $this->conn->commit();
+    }
+
+    /**
+     * TODO does it needed???
+     * @return bool
+     */
+    public function rollback()
+    {
+        return $this->conn->rollback();
+    }
+}
diff --git a/src/SmsConnector/SmsGatewayConnector.php b/src/SmsConnector/SmsGatewayConnector.php
index a1bf4832..89d3ee14 100644
--- a/src/SmsConnector/SmsGatewayConnector.php
+++ b/src/SmsConnector/SmsGatewayConnector.php
@@ -11,7 +11,7 @@
 
 namespace BikeShare\SmsConnector;
 
-use Bikeshare\SmsConnector\SmsGateway\SmsGateway;
+use BikeShare\SmsConnector\SmsGateway\SmsGateway;
 
 class SmsGatewayConnector extends AbstractConnector
 {
diff --git a/tests/Db/MysqliDbTest.php b/tests/Db/MysqliDbTest.php
new file mode 100644
index 00000000..1fb8d43a
--- /dev/null
+++ b/tests/Db/MysqliDbTest.php
@@ -0,0 +1,87 @@
+<?php
+
+namespace Test\BikeShare\Db;
+
+use BikeShare\Db\MysqliDb;
+use PHPUnit\Framework\TestCase;
+
+class MysqliDbTest extends TestCase
+{
+    public function setUp()
+    {
+        $db = new MysqliDb('server', 'user', 'password', 'dbname', true);
+        $mysqliMock = $this->createMock(\mysqli::class);
+
+        $reflection = new \ReflectionClass($db);
+        $reflection_property = $reflection->getProperty('conn');
+        $reflection_property->setAccessible(true);
+        $reflection_property->setValue($db, $mysqliMock);
+
+        $this->db = $db;
+        $this->conn = $mysqliMock;
+    }
+
+    public function testQuery()
+    {
+        $query = 'SELECT * FROM table';
+        $result = $this->createMock(\mysqli_result::class);
+        $this->conn->expects($this->once())
+            ->method('query')
+            ->with($query)
+            ->willReturn($result);
+
+        $this->assertSame($result, $this->db->query($query));
+    }
+    public function testQueryError()
+    {
+        $query = 'SELECT * FROM table';
+        $result = $this->createMock(\mysqli_result::class);
+        $this->conn->expects($this->once())
+            ->method('query')
+            ->with($query)
+            ->willReturn(false);
+        $this->conn->expects($this->once())
+            ->method('rollback');
+
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('DB error in : ' . $query);
+
+        $this->assertSame($result, $this->db->query($query));
+    }
+
+    public function testEscape()
+    {
+        $string = "string";
+        $escapedString = "escapedString";
+        $this->conn->expects($this->once())
+            ->method('real_escape_string')
+            ->with($string)
+            ->willReturn($escapedString);
+
+        $this->assertSame($escapedString, $this->db->escape($string));
+    }
+    public function testSetAutocommit()
+    {
+        $this->conn->expects($this->once())
+            ->method('autocommit')
+            ->with(false);
+
+        $this->db->setAutocommit(false);
+    }
+
+    public function testCommit()
+    {
+        $this->conn->expects($this->once())
+            ->method('commit');
+
+        $this->db->commit();
+    }
+
+    public function testRollback()
+    {
+        $this->conn->expects($this->once())
+            ->method('rollback');
+
+        $this->db->rollback();
+    }
+}
diff --git a/tests/SmsConnector/SmsConnectorFactory.php b/tests/SmsConnector/SmsConnectorFactory.php
index 98fa6374..03e0cedc 100644
--- a/tests/SmsConnector/SmsConnectorFactory.php
+++ b/tests/SmsConnector/SmsConnectorFactory.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Test\Bikeshare\SmsConnector;
+namespace Test\BikeShare\SmsConnector;
 
 use BikeShare\SmsConnector\DisabledConnector;
 use BikeShare\SmsConnector\EuroSmsConnector;