diff --git a/lib/Db/Answer.php b/lib/Db/Answer.php
index 7f812f8..e340612 100644
--- a/lib/Db/Answer.php
+++ b/lib/Db/Answer.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2019 Inigo Jiron <ijiron@terpmail.umd.edu>
  *
@@ -35,10 +37,18 @@ use OCP\AppFramework\Db\Entity;
  * @method integer getTimestamp()
  * @method void setTimestamp(integer $value)
  */
-class Answer extends Model {
+class Answer extends Entity {
+
+	/** @var int */
 	protected $formId;
+
+	/** @var int */
 	protected $questionId;
+
+	/** @var string */
 	protected $text;
+
+	/** @var int */
 	protected $timestamp;
 
 	/**
@@ -51,7 +61,7 @@ class Answer extends Model {
 		$this->addType('timestamp', 'integer');
 	}
 
-	public function read() {
+	public function read(): array {
 		return [
 			'id' => $this->getId(),
 			'formId' => $this->getFormId(),
diff --git a/lib/Db/AnswerMapper.php b/lib/Db/AnswerMapper.php
index e7e830f..f002ea0 100644
--- a/lib/Db/AnswerMapper.php
+++ b/lib/Db/AnswerMapper.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2019 Inigo Jiron <ijiron@terpmail.umd.edu>
  *
@@ -35,7 +37,7 @@ class AnswerMapper extends QBMapper {
 	 * @param IDBConnection $db
 	 */
 	public function __construct(IDBConnection $db) {
-		parent::__construct($db, 'forms_answers', '\OCA\Forms\Db\Answer');
+		parent::__construct($db, 'forms_answers', Answer::class);
 	}
 
 	// TODO: Change below functions to search by form and question id
@@ -47,7 +49,7 @@ class AnswerMapper extends QBMapper {
 	 * @return Answer[]
 	 */
 
-	public function findByForm($formId, $questionId) {
+	public function findByForm(int $formId, int $questionId): array {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
@@ -66,7 +68,7 @@ class AnswerMapper extends QBMapper {
 	 * @param int $formId
 	 * @param int $questionId
 	 */
-	public function deleteByFormAndQuestion($formId, $questionId) {
+	public function deleteByFormAndQuestion(int $formId, int $questionId): void {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->delete($this->getTableName())
@@ -83,7 +85,7 @@ class AnswerMapper extends QBMapper {
 	/**
 	 * @param int $formId
 	 */
-	public function deleteByForm($formId) {
+	public function deleteByForm(int $formId): void {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->delete($this->getTableName())
diff --git a/lib/Db/Event.php b/lib/Db/Event.php
index 6d0f5b7..d05e911 100644
--- a/lib/Db/Event.php
+++ b/lib/Db/Event.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
  *
@@ -45,7 +46,7 @@ use OCP\AppFramework\Db\Entity;
  * @method integer getIsAnonymous()
  * @method void setIsAnonymous(integer $value)
  */
-class Event extends Model {
+class Event extends Entity {
 	protected $title;
 	protected $description;
 	protected $owner;
diff --git a/lib/Db/EventMapper.php b/lib/Db/EventMapper.php
index 9cf76ea..e342d4e 100644
--- a/lib/Db/EventMapper.php
+++ b/lib/Db/EventMapper.php
@@ -35,7 +35,7 @@ class EventMapper extends QBMapper {
 	 * @param IDBConnection $db
 	 */
 	public function __construct(IDBConnection $db) {
-		parent::__construct($db, 'forms_events', '\OCA\Forms\Db\Event');
+		parent::__construct($db, 'forms_events', Event::class);
 	}
 
 	/**
@@ -44,7 +44,7 @@ class EventMapper extends QBMapper {
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException if more than one result
 	 * @return Event
 	 */
-	public function find($id) {
+	public function find(int $id): Event {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
@@ -62,7 +62,7 @@ class EventMapper extends QBMapper {
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException if more than one result
 	 * @return Event
 	 */
-	public function findByHash($hash) {
+	public function findByHash(string $hash): Event {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
@@ -78,7 +78,7 @@ class EventMapper extends QBMapper {
 	 * @throws \OCP\AppFramework\Db\DoesNotExistException if not found
 	 * @return Event[]
 	 */
-	public function findAll() {
+	public function findAll(): array {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
diff --git a/lib/Db/Model.php b/lib/Db/Model.php
deleted file mode 100644
index e392310..0000000
--- a/lib/Db/Model.php
+++ /dev/null
@@ -1,39 +0,0 @@
-<?php
-/**
- * @copyright Copyright (c) 2017 Kai Schröer <git@schroeer.co>
- *
- * @author Kai Schröer <git@schroeer.co>
- *
- * @license GNU AGPL version 3 or any later version
- *
- *  This program is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU Affero General Public License as
- *  published by the Free Software Foundation, either version 3 of the
- *  License, or (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU Affero General Public License for more details.
- *
- *  You should have received a copy of the GNU Affero General Public License
- *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-namespace OCA\Forms\Db;
-
-use OCP\AppFramework\Db\Entity;
-
-abstract class Model extends Entity {
-	/**
-	 * FactoryMuffin checks for the existence of setters with method_exists($obj, $attr) but that returns false.
-	 * By overwriting the __set() magic method we can trigger the changed flag on $obj->attr assignment.
-	 *
-	 * @param $name
-	 * @param $value
-	 */
-	public function __set($name, $value) {
-		$this->setter($name, [$value]);
-	}
-}
diff --git a/lib/Db/Notification.php b/lib/Db/Notification.php
index 5571ffb..51b6be9 100644
--- a/lib/Db/Notification.php
+++ b/lib/Db/Notification.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
  *
@@ -32,7 +33,7 @@ use OCP\AppFramework\Db\Entity;
  * @method integer getFormId()
  * @method void setFormId(integer $value)
  */
-class Notification extends Model {
+class Notification extends Entity {
 	protected $userId;
 	protected $formId;
 
diff --git a/lib/Db/NotificationMapper.php b/lib/Db/NotificationMapper.php
index c3a2837..f76c6e8 100644
--- a/lib/Db/NotificationMapper.php
+++ b/lib/Db/NotificationMapper.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
  *
@@ -31,7 +32,7 @@ use OCP\AppFramework\Db\QBMapper;
 class NotificationMapper extends QBMapper {
 
 	public function __construct(IDBConnection $db) {
-		parent::__construct($db, 'forms_notif', '\OCA\Forms\Db\Notification');
+		parent::__construct($db, 'forms_notif', Notification::class);
 	}
 
 	/**
@@ -41,7 +42,7 @@ class NotificationMapper extends QBMapper {
 	 * @return Notification[]
 	 */
 
-	 public function findAllByForm($formId) {
+	 public function findAllByForm(int $formId): array {
 		 $qb = $this->db->getQueryBuilder();
 
 		  $qb->select('*')
@@ -59,9 +60,9 @@ class NotificationMapper extends QBMapper {
 	 * @param string $userId
 	 * @throws \OCP\AppFramework\Db\DoesNotExistException if not found
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException if more than one result
-	 * @return Notification
+	 * @return Notification[]
 	 */
-	public function findByUserAndForm($formId, $userId) {
+	public function findByUserAndForm(int $formId, string $userId): array {
 		$qb = $this->db->getQueryBuilder();
 
 		 $qb->select('*')
@@ -79,7 +80,7 @@ class NotificationMapper extends QBMapper {
 	/**
 	 * @param int $formId
 	 */
-	 public function deleteByForm($formId) {
+	 public function deleteByForm(int $formId): void {
  		$qb = $this->db->getQueryBuilder();
 
  		$qb->delete($this->getTableName())
diff --git a/lib/Db/Question.php b/lib/Db/Question.php
index 8dc9a9a..4062edd 100644
--- a/lib/Db/Question.php
+++ b/lib/Db/Question.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types=1);
 /**
  * @copyright Copyright (c) 2019 Inigo Jiron <ijiron@terpmail.umd.edu>
  *
@@ -35,7 +36,7 @@ use OCP\AppFramework\Db\Entity;
  * @method integer getTimestamp()
  * @method void setTimestamp(integer $value)
  */
-class Question extends Model {
+class Question extends Entity {
 	protected $formId;
 	protected $formQuestionType;
 	protected $formQuestionText;
@@ -49,7 +50,7 @@ class Question extends Model {
 		$this->addType('timestamp', 'integer');
 	}
 
-	public function read() {
+	public function read(): array {
 		return [
 			'id' => $this->getId(),
 			'formId' => $this->getFormId(),
diff --git a/lib/Db/QuestionMapper.php b/lib/Db/QuestionMapper.php
index 6ea92b8..cadd59e 100644
--- a/lib/Db/QuestionMapper.php
+++ b/lib/Db/QuestionMapper.php
@@ -35,7 +35,7 @@ class QuestionMapper extends QBMapper {
 	 * @param IDBConnection $db
 	 */
 	public function __construct(IDBConnection $db) {
-		parent::__construct($db, 'forms_questions', '\OCA\Forms\Db\Question');
+		parent::__construct($db, 'forms_questions', Question::class);
 	}
 
 	/**
@@ -44,7 +44,7 @@ class QuestionMapper extends QBMapper {
 	 * @return Option[]
 	 */
 
-	public function findByForm($formId) {
+	public function findByForm(int $formId): array {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
@@ -59,7 +59,7 @@ class QuestionMapper extends QBMapper {
 	/**
 	 * @param int $formId
 	 */
-	public function deleteByForm($formId) {
+	public function deleteByForm(int $formId): void {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->delete($this->getTableName())
diff --git a/lib/Db/Vote.php b/lib/Db/Vote.php
index 85544a4..49560fd 100644
--- a/lib/Db/Vote.php
+++ b/lib/Db/Vote.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
  *
@@ -41,7 +43,7 @@ use OCP\AppFramework\Db\Entity;
  * @method string getVoteOptionType()
  * @method void setVoteOptionType(string $value)
  */
-class Vote extends Model {
+class Vote extends Entity {
 	protected $formId;
 	protected $userId;
 	protected $voteOptionId;
@@ -57,7 +59,7 @@ class Vote extends Model {
 		$this->addType('voteOptionId', 'integer');
 	}
 
-	public function read() {
+	public function read(): array {
 		return [
 			'id' => $this->getId(),
 			'userId' => $this->getUserId(),
diff --git a/lib/Db/VoteMapper.php b/lib/Db/VoteMapper.php
index 4ad723a..fb44542 100644
--- a/lib/Db/VoteMapper.php
+++ b/lib/Db/VoteMapper.php
@@ -35,7 +35,7 @@ class VoteMapper extends QBMapper {
 	 * @param IDBConnection $db
 	 */
 	public function __construct(IDBConnection $db) {
-		parent::__construct($db, 'forms_votes', '\OCA\Forms\Db\Vote');
+		parent::__construct($db, 'forms_votes', VoteMapper::class);
 	}
 
 	/**
@@ -44,7 +44,7 @@ class VoteMapper extends QBMapper {
 	 * @return Comment[]
 	 */
 
-	public function findByForm($formId) {
+	public function findByForm(int $formId): array {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('*')
@@ -59,9 +59,9 @@ class VoteMapper extends QBMapper {
 	/**
 	 * @param int $formId
 	 * @throws \OCP\AppFramework\Db\DoesNotExistException if not found
-	 * @return Array
+	 * @return array
 	 */
-	public function findParticipantsByForm($formId, $limit = null, $offset = null) {
+	public function findParticipantsByForm(int $formId, $limit = null, $offset = null): array {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->select('user_id')
@@ -77,7 +77,7 @@ class VoteMapper extends QBMapper {
 	 * @param int $formId
 	 * @param string $userId
 	 */
-	 public function deleteByFormAndUser($formId, $userId) {
+	 public function deleteByFormAndUser(int $formId, string $userId): void {
 		$qb = $this->db->getQueryBuilder();
 
         $qb->delete($this->getTableName())
@@ -94,7 +94,7 @@ class VoteMapper extends QBMapper {
 	/**
 	* @param int $formId
 	*/
-	public function deleteByForm($formId) {
+	public function deleteByForm(int $formId): void {
 		$qb = $this->db->getQueryBuilder();
 
 		$qb->delete($this->getTableName())