diff --git a/src/export.php b/src/export.php
index 9809435..a53abfc 100644
--- a/src/export.php
+++ b/src/export.php
@@ -25,7 +25,7 @@ else $sqlSort .= "ow ASC";
 
 $data = array();
 $q = $db->dq("SELECT *, duedate IS NULL AS ddn FROM {$db->prefix}todolist WHERE list_id=$listId $sqlSort");
-while($r = $q->fetch_assoc($q))
+while($r = $q->fetchAssoc())
 {
 	$data[] = $r;
 }
diff --git a/src/feed.php b/src/feed.php
index ffbe826..8c4c80f 100644
--- a/src/feed.php
+++ b/src/feed.php
@@ -61,7 +61,7 @@ function fillData(&$data, $listId, $field, $sqlWhere )
 	$lang = Lang::instance();
 	$db = DBConnection::instance();
 	$q = $db->dq("SELECT * FROM {$db->prefix}todolist WHERE list_id=$listId $sqlWhere ORDER BY $field DESC LIMIT 100");
-	while ($r = $q->fetch_assoc($q))
+	while ($r = $q->fetchAssoc())
 	{
 		if ($r['prio'] > 0) {
 			$r['prio'] = '+'.$r['prio'];
diff --git a/src/includes/class.db.mysql.php b/src/includes/class.db.mysql.php
index 852453a..eaa57ab 100644
--- a/src/includes/class.db.mysql.php
+++ b/src/includes/class.db.mysql.php
@@ -6,7 +6,7 @@
 */
 
 // ---------------------------------------------------------------------------- //
-class DatabaseResult_Mysql
+class DatabaseResult_Mysql extends DatabaseResult_Abstract
 {
 	private $q;
 	private $affected;
@@ -26,12 +26,12 @@ class DatabaseResult_Mysql
 		}
 	}
 
-	function fetch_row()
+	function fetchRow()
 	{
 		return $this->q->fetch(PDO::FETCH_NUM);
 	}
 
-	function fetch_assoc()
+	function fetchAssoc()
 	{
 		return $this->q->fetch(PDO::FETCH_ASSOC);
 	}
@@ -43,7 +43,7 @@ class DatabaseResult_Mysql
 }
 
 // ---------------------------------------------------------------------------- //
-class Database_Mysql
+class Database_Mysql extends Database_Abstract
 {
 	private $dbh;
 	private $affected = null;
@@ -55,8 +55,12 @@ class Database_Mysql
 	{
 	}
 
-	function connect($host, $user, $pass, $db)
+	function connect($params)
 	{
+		$host = $params['host'];
+		$user = $params['user'];
+		$pass = $params['password'];
+		$db = $params['db'];
 		$options = array(
 			PDO::MYSQL_ATTR_FOUND_ROWS => true,
 			PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
@@ -77,7 +81,7 @@ class Database_Mysql
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_row();
+		$res = $q->fetchRow();
 		if ($res === false) return NULL;
 
 		if (sizeof($res) > 1) return $res;
@@ -92,14 +96,14 @@ class Database_Mysql
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_assoc();
+		$res = $q->fetchAssoc();
 		if ($res === false) return NULL;
 
 		if (sizeof($res) > 1) return $res;
 		else return $res[0];
 	}
 
-	function dq($query, $p = NULL)
+	function dq($query, $p = NULL) : DatabaseResult_Abstract
 	{
 		return $this->_dq($query, $p);
 	}
@@ -109,10 +113,11 @@ class Database_Mysql
 	*/
 	function ex($query, $p = NULL)
 	{
-		return $this->_dq($query, $p, true);
+		$dbr = $this->_dq($query, $p, true);
+		return $this->affected();
 	}
 
-	private function _dq($query, $p = NULL, $resultless = 0)
+	private function _dq($query, $p = NULL, $resultless = 0) : DatabaseResult_Abstract
 	{
 		if (!isset($p)) $p = array();
 		elseif (!is_array($p)) $p = array($p);
@@ -155,12 +160,12 @@ class Database_Mysql
 		return '\''. sprintf($format, $s). '\'';
 	}
 
-	function last_insert_id()
+	function lastInsertId()
 	{
 		return $this->dbh->lastInsertId();
 	}
 
-	function table_exists($table)
+	function tableExists($table)
 	{
 		$r = $this->sq("SELECT 1 FROM information_schema.tables WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?",
 						array($this->dbname, $table) );
diff --git a/src/includes/class.db.mysqli.php b/src/includes/class.db.mysqli.php
index 515030e..024a856 100644
--- a/src/includes/class.db.mysqli.php
+++ b/src/includes/class.db.mysqli.php
@@ -6,7 +6,7 @@
 */
 
 // ---------------------------------------------------------------------------- //
-class DatabaseResult_Mysql
+class DatabaseResult_Mysql extends DatabaseResult_Abstract
 {
 	private $q; //mysqli_result
 
@@ -15,19 +15,19 @@ class DatabaseResult_Mysql
 		$this->q = $dbh->query($query); //throws mysqli_sql_exception
 	}
 
-	function fetch_row()
+	function fetchRow()
 	{
 		return $this->q->fetch_row();
 	}
 
-	function fetch_assoc()
+	function fetchAssoc()
 	{
 		return $this->q->fetch_assoc();
 	}
 }
 
 // ---------------------------------------------------------------------------- //
-class Database_Mysql
+class Database_Mysql extends Database_Abstract
 {
 	private $dbh; //mysqli
 	private $dbname;
@@ -39,14 +39,18 @@ class Database_Mysql
 		mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
 	}
 
-	function connect($host, $user, $pass, $db)
+	function connect($params)
 	{
+		$host = $params['host'];
+		$user = $params['user'];
+		$pass = $params['password'];
+		$db = $params['db'];
 		$this->dbname = $db;
 		$this->dbh = new mysqli($host, $user, $pass, $db); //throws mysqli_sql_exception
 		return true;
 	}
 
-	function last_insert_id()
+	function lastInsertId()
 	{
 		return $this->dbh->insert_id;
 	}
@@ -55,7 +59,7 @@ class Database_Mysql
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_row();
+		$res = $q->fetchRow();
 		if ($res === false || $res === null) return NULL;
 
 		if (sizeof($res) > 1) return $res;
@@ -66,13 +70,13 @@ class Database_Mysql
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_assoc();
+		$res = $q->fetchAssoc();
 		if ($res === false || $res === null) return NULL;
 
 		return $res;
 	}
 
-	function dq($query, $p = NULL)
+	function dq($query, $p = NULL) : DatabaseResult_Abstract
 	{
 		return $this->_dq($query, $p);
 	}
@@ -86,7 +90,7 @@ class Database_Mysql
 		return $this->affected();
 	}
 
-	private function _dq($query, $p = NULL, $resultless = 0)
+	private function _dq($query, $p = NULL, $resultless = 0) : DatabaseResult_Abstract
 	{
 		if (!isset($p)) $p = array();
 		elseif (!is_array($p)) $p = array($p);
@@ -127,7 +131,7 @@ class Database_Mysql
 		return '\''. sprintf($format, $s). '\'';
 	}
 
-	function table_exists($table)
+	function tableExists($table)
 	{
 		$r = $this->sq("SELECT 1 FROM information_schema.tables WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?",
 						array($this->dbname, $table) );
diff --git a/src/includes/class.db.sqlite3.php b/src/includes/class.db.sqlite3.php
index 2182869..69a683c 100644
--- a/src/includes/class.db.sqlite3.php
+++ b/src/includes/class.db.sqlite3.php
@@ -5,7 +5,7 @@
 	Licensed under the GNU GPL v2 license. See file COPYRIGHT for details.
 */
 
-class DatabaseResult_Sqlite3
+class DatabaseResult_Sqlite3 extends DatabaseResult_Abstract
 {
 	private $q;
 	private $affected;
@@ -25,12 +25,12 @@ class DatabaseResult_Sqlite3
 		}
 	}
 
-	function fetch_row()
+	function fetchRow()
 	{
 		return $this->q->fetch(PDO::FETCH_NUM);
 	}
 
-	function fetch_assoc()
+	function fetchAssoc()
 	{
 		return $this->q->fetch(PDO::FETCH_ASSOC);
 	}
@@ -42,7 +42,7 @@ class DatabaseResult_Sqlite3
 
 }
 
-class Database_Sqlite3
+class Database_Sqlite3 extends Database_Abstract
 {
 	private $dbh;
 	private $affected = null;
@@ -53,8 +53,9 @@ class Database_Sqlite3
 	{
 	}
 
-	function connect($filename)
+	function connect($params)
 	{
+		$filename = $params['filename'];
 		$options = array(
 			PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
 		);
@@ -69,7 +70,7 @@ class Database_Sqlite3
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_row();
+		$res = $q->fetchRow();
 		if ($res === false) return NULL;
 
 		if (sizeof($res) > 1) return $res;
@@ -83,7 +84,7 @@ class Database_Sqlite3
 	{
 		$q = $this->_dq($query, $p);
 
-		$res = $q->fetch_assoc();
+		$res = $q->fetchAssoc();
 		if ($res === false) return NULL;
 		return $res;
 	}
@@ -91,7 +92,7 @@ class Database_Sqlite3
 	/*
 		SELECT queries for multiple rows
 	*/
-	function dq($query, $p = NULL)
+	function dq($query, $p = NULL) : DatabaseResult_Abstract
 	{
 		return $this->_dq($query, $p);
 	}
@@ -105,7 +106,7 @@ class Database_Sqlite3
 		return $this->affected();
 	}
 
-	private function _dq($query, $p = NULL, $resultless = 0)
+	private function _dq($query, $p = NULL, $resultless = 0) : DatabaseResult_Abstract
 	{
 		if (!isset($p)) $p = array();
 		elseif (!is_array($p)) $p = array($p);
@@ -148,12 +149,12 @@ class Database_Sqlite3
 		return $this->dbh->quote(sprintf($format, $s)). " ESCAPE '\'";
 	}
 
-	function last_insert_id()
+	function lastInsertId()
 	{
 		return $this->dbh->lastInsertId();
 	}
 
-	function table_exists($table)
+	function tableExists($table)
 	{
 		$exists = $this->sq("SELECT 1 FROM sqlite_master WHERE type='table' AND name=?", $table);
 		if ($exists == "1") {
diff --git a/src/includes/common.php b/src/includes/common.php
index be9d68c..ca30ea3 100644
--- a/src/includes/common.php
+++ b/src/includes/common.php
@@ -115,13 +115,13 @@ class DBConnection
 {
 	protected static $instance;
 
-	public static function init($instance)
+	public static function init(Database_Abstract $instance) : Database_Abstract
 	{
 		self::$instance = $instance;
 		return $instance;
 	}
 
-	public static function instance()
+	public static function instance() : Database_Abstract
 	{
         if (!isset(self::$instance)) {
 			throw new Exception("DBConnection is not initialized");
@@ -136,4 +136,26 @@ class DBConnection
 	}
 }
 
+abstract class Database_Abstract
+{
+	var $lastQuery = null;
+	var $prefix = '';
+	abstract function connect($params);
+	abstract function sq($query, $p = NULL);
+	abstract function sqa($query, $p = NULL);
+	abstract function dq($query, $p = NULL) : DatabaseResult_Abstract;
+	abstract function ex($query, $p = NULL);
+	abstract function affected();
+	abstract function quote($s);
+	abstract function quoteForLike($format, $s);
+	abstract function lastInsertId();
+	abstract function tableExists($table);
+}
+
+abstract class DatabaseResult_Abstract
+{
+	abstract function fetchRow();
+	abstract function fetchAssoc();
+}
+
 ?>
\ No newline at end of file
diff --git a/src/init.php b/src/init.php
index e803e2d..28149ec 100644
--- a/src/init.php
+++ b/src/init.php
@@ -47,7 +47,12 @@ if (Config::get('db') == 'mysql')
 	else require_once(MTTINC. 'class.db.mysql.php');
 	$db = DBConnection::init(new Database_Mysql);
 	try {
-		$db->connect(Config::get('mysql.host'), Config::get('mysql.user'), Config::get('mysql.password'), Config::get('mysql.db'));
+		$db->connect( array(
+			'host' => Config::get('mysql.host'),
+			'user' => Config::get('mysql.user'),
+			'password' => Config::get('mysql.password'),
+			'db' => Config::get('mysql.db')
+		));
 	}
 	catch(Exception $e) {
 		logAndDie("Failed to connect to mysql database: ". $e->getMessage());
@@ -60,7 +65,7 @@ elseif(Config::get('db') == 'sqlite')
 {
 	require_once(MTTINC. 'class.db.sqlite3.php');
 	$db = DBConnection::init(new Database_Sqlite3);
-	$db->connect(MTTPATH. 'db/todolist.db');
+	$db->connect( array( 'filename' => MTTPATH. 'db/todolist.db' ) );
 }
 else {
 	# It seems not installed
diff --git a/src/setup.php b/src/setup.php
index 818cc39..c6d5179 100644
--- a/src/setup.php
+++ b/src/setup.php
@@ -31,6 +31,7 @@ if($config['db'] != '')
 	{
 		die("Access denied!<br> Disable password protection or Log in.");
 	}
+	$db = DBConnection::instance();
 	$dbtype = (strtolower(get_class($db)) == 'database_mysql') ? 'mysql' : 'sqlite';
 }
 else
@@ -42,7 +43,7 @@ else
 	Config::loadConfig($config);
 	unset($config);
 
-	$db = 0;
+	$db = null;
 	$dbtype = '';
 }
 
@@ -270,12 +271,12 @@ echo "Done<br><br> <b>Attention!</b> Delete this file for security reasons.";
 printFooter();
 
 
-function get_ver($db, $dbtype)
+function get_ver(Database_Abstract $db, $dbtype)
 {
 	if(!$db || $dbtype == '') return '';
-	if(!$db->table_exists($db->prefix.'todolist')) return '';
+	if(!$db->tableExists($db->prefix.'todolist')) return '';
 	$v = '1.0';
-	if(!$db->table_exists($db->prefix.'tags')) return $v;
+	if(!$db->tableExists($db->prefix.'tags')) return $v;
 	$v = '1.1';
 	if($dbtype == 'mysql') {
 		if(!has_field_mysql($db, $db->prefix.'todolist', 'duedate')) return $v;
@@ -283,7 +284,7 @@ function get_ver($db, $dbtype)
 		if(!has_field_sqlite($db, $db->prefix.'todolist', 'duedate')) return $v;
 	}
 	$v = '1.2';
-	if(!$db->table_exists($db->prefix.'lists')) return $v;
+	if(!$db->tableExists($db->prefix.'lists')) return $v;
 	$v = '1.3.0';
 	if($dbtype == 'mysql') {
 		if(!has_field_mysql($db, $db->prefix.'todolist', 'd_completed')) return $v;
@@ -313,19 +314,19 @@ function printFooter()
 }
 
 
-function has_field_sqlite($db, $table, $field)
+function has_field_sqlite(Database_Abstract $db, $table, $field)
 {
 	$q = $db->dq("PRAGMA table_info(". $db->quote($table). ")");
-	while($r = $q->fetch_row()) {
+	while($r = $q->fetchRow()) {
 		if($r[1] == $field) return true;
 	}
 	return false;
 }
 
-function has_field_mysql($db, $table, $field)
+function has_field_mysql(Database_Abstract $db, $table, $field)
 {
 	$q = $db->dq("DESCRIBE `$table`");
-	while($r = $q->fetch_row()) {
+	while($r = $q->fetchRow()) {
 		if($r[0] == $field) return true;
 	}
 	return false;
@@ -351,7 +352,12 @@ function testConnect(&$error)
 			}
 
 			$db = new Database_Mysql;
-			$db->connect(Config::get('mysql.host'), Config::get('mysql.user'), Config::get('mysql.password'), Config::get('mysql.db'));
+			$db->connect(array(
+				'host' => Config::get('mysql.host'),
+				'user' => Config::get('mysql.user'),
+				'password' => Config::get('mysql.password'),
+				'db' => Config::get('mysql.db')
+			));
 		}
 		else
 		{
@@ -362,7 +368,7 @@ function testConnect(&$error)
 
 			require_once(MTTINC. 'class.db.sqlite3.php');
 			$db = new Database_Sqlite3;
-			$db->connect(MTTPATH. 'db/todolist.db');
+			$db->connect( array( 'filename' => MTTPATH. 'db/todolist.db' ) );
 		}
 	} catch(Exception $e) {
 		$error = $e->getMessage();
@@ -380,7 +386,7 @@ function myExceptionHandler($e)
 
 
 ### 1.1-1.2 ##########
-function update_11_12($db, $dbtype)
+function update_11_12(Database_Abstract $db, $dbtype)
 {
 	if($dbtype == 'mysql') $db->ex("ALTER TABLE todolist ADD `duedate` DATE default NULL");
 	else $db->ex("ALTER TABLE todolist ADD duedate DATE default NULL");
@@ -390,7 +396,7 @@ function update_11_12($db, $dbtype)
 	$db->ex("DELETE FROM tags");
 	$db->ex("DELETE FROM tag2task");
 	$q = $db->dq("SELECT id,tags FROM todolist");
-	while($r = $q->fetch_assoc())
+	while($r = $q->fetchAssoc())
 	{
 		if($r['tags'] == '') continue;
 		$tag_ids = prepare_tags($r['tags']);
@@ -427,7 +433,7 @@ function get_or_create_tag($name)
 
 	# need to create tag
 	$db->ex("INSERT INTO tags (name) VALUES (?)", $name);
-	return array($db->last_insert_id(), $name);
+	return array($db->lastInsertId(), $name);
 }
 
 function update_task_tags($id, $tag_ids)
@@ -442,7 +448,7 @@ function update_task_tags($id, $tag_ids)
 ### end 1.1-1.2 #####
 
 ### 1.2-1.3 ##########
-function update_12_13($db, $dbtype)
+function update_12_13(Database_Abstract $db, $dbtype)
 {
 	# update config
 	Config::save();
@@ -504,7 +510,7 @@ function update_12_13($db, $dbtype)
 
 
 ### 1.3.0 to 1.3.1 ##########
-function update_130_131($db, $dbtype)
+function update_130_131(Database_Abstract $db, $dbtype)
 {
 	$tz = null;
 	if(isset($_POST['tz'])) {
@@ -617,7 +623,7 @@ function update_130_131($db, $dbtype)
 ### end of 1.3.0 to 1.3.1 ##########
 
 ### update v1.3.1 to v1.4 ##########
-function update_131_14($db, $dbtype)
+function update_131_14(Database_Abstract $db, $dbtype)
 {
 	$db->ex("BEGIN");
 	if($dbtype=='mysql')
@@ -697,7 +703,7 @@ function update_131_14($db, $dbtype)
 
 	$q = $db->dq("SELECT id,list_id,tags FROM {$db->prefix}todolist WHERE tags != ''");
 	$ar = array();
-	while($r = $q->fetch_assoc()) $ar[] = $r;
+	while($r = $q->fetchAssoc()) $ar[] = $r;
 	foreach($ar as $r)
 	{
 			$aTags = v14_prepareTags($r['tags']);
@@ -720,14 +726,14 @@ function update_131_14($db, $dbtype)
 	# add UUID
 	$q = $db->dq("SELECT id FROM {$db->prefix}todolist");
 	$ar = array();
-	while($r = $q->fetch_assoc()) $ar[] = $r;
+	while($r = $q->fetchAssoc()) $ar[] = $r;
 	foreach($ar as $r) {
 		$db->ex("UPDATE {$db->prefix}todolist SET uuid=? WHERE id=".$r['id'], array(generateUUID()) );
 	}
 
 	$q = $db->dq("SELECT id FROM {$db->prefix}lists");
 	$ar = array();
-	while($r = $q->fetch_assoc()) $ar[] = $r;
+	while($r = $q->fetchAssoc()) $ar[] = $r;
 	foreach($ar as $r) {
 		$db->ex("UPDATE {$db->prefix}lists SET uuid=? WHERE id=".$r['id'], array(generateUUID()) );
 	}
@@ -774,7 +780,7 @@ function v14_getOrCreateTag($name)
 	if($tagId) return array('id'=>$tagId, 'name'=>$name);
 
 	$db->ex("INSERT INTO {$db->prefix}tags (name) VALUES (?)", array($name));
-	return array('id'=>$db->last_insert_id(), 'name'=>$name);
+	return array('id'=>$db->lastInsertId(), 'name'=>$name);
 }
 
 function v14_addTaskTags($taskId, $tagIds, $listId)