diff --git a/lib/Db/NoteShareMapper.php b/lib/Db/NoteShareMapper.php
index 50fcc67..4b7111e 100644
--- a/lib/Db/NoteShareMapper.php
+++ b/lib/Db/NoteShareMapper.php
@@ -5,6 +5,8 @@ use OCP\IDBConnection;
 use OCP\AppFramework\Db\Mapper;
 use OCP\AppFramework\Db\DoesNotExistException;
 
+use OCA\QuickNotes\Db\NoteShare;
+
 class NoteShareMapper extends Mapper {
 
 	public function __construct(IDBConnection $db) {
@@ -16,40 +18,43 @@ class NoteShareMapper extends Mapper {
 		return $this->findEntity($sql, [$id, $userId]);
 	}*/
 
-	public function findForUser($userId) {
+	public function findForUser(string $userId): array {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE shared_user = ?';
 		return $this->findEntities($sql, [$userId]);
 	}
 
-	public function findForGroup($groupId) {
+	public function findForGroup($groupId): array {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE shared_group = ?';
 		return $this->findEntities($sql, [$groupId]);
 	}
 
-	public function findByNoteAndUser($noteId, $userId) {
+	public function findByNoteAndUser($noteId, $userId): NoteShare {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE shared_user = ? AND note_id = ?';
 		return $this->findEntity($sql, [$userId, $noteId]);
 	}
 
-	public function findByNoteAndGroup($noteId, $groupId) {
+	public function findByNoteAndGroup($noteId, $groupId): NoteShare {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE shared_group = ? AND note_id = ?';
 		return $this->findEntity($sql, [$groupId, $noteId]);
 	}
 
-	public function getSharesForNote($noteId) {
+	public function getSharesForNote(int $noteId): array {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE note_id = ?';
 		return $this->findEntities($sql, [$noteId]);
 	}
 
-	public function deleteByNoteId($noteId) {
+	public function deleteByNoteId(int $noteId): void {
 		$sql = 'DELETE FROM *PREFIX*quicknotes_shares WHERE note_id = ?';
 		$this->execute($sql, [$noteId]);
 	}
 
-	public function existsByNoteAndUser($noteId, $userId) {
+	/**
+	 * @return bool
+	 */
+	public function existsByNoteAndUser(int $noteId, $userId) {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_shares WHERE shared_user = ? AND note_id = ?';
 		try {
-			return $this->findEntities($sql, [$userId, $noteId]);
+			$this->findEntities($sql, [$userId, $noteId]);
 		} catch (DoesNotExistException $e) {
 			return false;
 		}
diff --git a/lib/Db/NoteTagMapper.php b/lib/Db/NoteTagMapper.php
index a5f4b5a..a14db01 100644
--- a/lib/Db/NoteTagMapper.php
+++ b/lib/Db/NoteTagMapper.php
@@ -3,6 +3,9 @@ namespace OCA\QuickNotes\Db;
 
 use OCP\IDBConnection;
 use OCP\AppFramework\Db\Mapper;
+use OCP\AppFramework\Db\DoesNotExistException;
+
+use OCA\QuickNotes\Db\NoteTag;
 
 class NoteTagMapper extends Mapper {
 
@@ -10,25 +13,28 @@ class NoteTagMapper extends Mapper {
 		parent::__construct($db, 'quicknotes_note_tags', '\OCA\QuickNotes\Db\NoteTag');
 	}
 
-	public function find($id, $userId) {
+	public function find($id, $userId): NoteTag {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_note_tags WHERE id = ? AND user_id = ?';
 		return $this->findEntity($sql, [$id, $userId]);
 	}
 
-	public function findAll($userId) {
+	public function findAll($userId): array {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_note_tags WHERE user_id = ?';
 		return $this->findEntities($sql, [$userId]);
 	}
 
-	public function findNoteTag($userId, $noteId, $tagId) {
+	public function findNoteTag(string $userId, int $noteId, $tagId): NoteTag {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_note_tags WHERE user_id = ? AND note_id = ? AND tag_id = ?';
 		return $this->findEntity($sql, [$userId, $noteId, $tagId]);
 	}
 
-	public function noteTagExists($userId, $noteId, $tagId) {
+	/**
+	 * @return bool
+	 */
+	public function noteTagExists(string $userId, int $noteId, int $tagId): bool {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_note_tags WHERE user_id = ? AND note_id = ? AND tag_id = ?';
 		try {
-			return $this->findEntities($sql, [$userId, $noteId, $tagId]);
+			$this->findEntities($sql, [$userId, $noteId, $tagId]);
 		} catch (DoesNotExistException $e) {
 			return false;
 		}
diff --git a/lib/Db/TagMapper.php b/lib/Db/TagMapper.php
index b4a866f..cdcb7bd 100644
--- a/lib/Db/TagMapper.php
+++ b/lib/Db/TagMapper.php
@@ -3,6 +3,9 @@ namespace OCA\QuickNotes\Db;
 
 use OCP\IDBConnection;
 use OCP\AppFramework\Db\Mapper;
+use OCP\AppFramework\Db\DoesNotExistException;
+
+use OCA\QuickNotes\Db\Tag;
 
 class TagMapper extends Mapper {
 
@@ -10,17 +13,17 @@ class TagMapper extends Mapper {
 		parent::__construct($db, 'quicknotes_tags', '\OCA\QuickNotes\Db\Tag');
 	}
 
-	public function find($id, $userId) {
+	public function find($id, $userId): Tag {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_tags WHERE id = ? AND user_id = ?';
 		return $this->findEntity($sql, [$id, $userId]);
 	}
 
-	public function findAll($userId) {
+	public function findAll($userId): array {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_tags WHERE user_id = ?';
 		return $this->findEntities($sql, [$userId]);
 	}
 
-	public function getTagsForNote($userId, $noteId) {
+	public function getTagsForNote(string $userId, int $noteId): array {
 		$sql = 'SELECT T.id, T.name FROM *PREFIX*quicknotes_tags T ';
 		$sql.= 'INNER JOIN *PREFIX*quicknotes_note_tags NT ';
 		$sql.= 'ON T.id = NT.tag_id ';
@@ -28,15 +31,18 @@ class TagMapper extends Mapper {
 		return $this->findEntities($sql, [$userId, $noteId]);
 	}
 
-	public function getTag($userId, $name) {
+	public function getTag(string $userId, $name): Tag {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_tags WHERE user_id = ? AND name = ?';
 		return $this->findEntity($sql, [$userId, $name]);
 	}
 
-	public function tagExists($userId, $name) {
+	/**
+	 * @return bool
+	 */
+	public function tagExists(string $userId, $name): bool {
 		$sql = 'SELECT * FROM *PREFIX*quicknotes_tags WHERE user_id = ? AND name = ?';
 		try {
-			return $this->findEntities($sql, [$userId, $name]);
+			$this->findEntities($sql, [$userId, $name]);
 		} catch (DoesNotExistException $e) {
 			return false;
 		}
@@ -46,6 +52,6 @@ class TagMapper extends Mapper {
 	public function dropOld () {
 		$sql = 'DELETE FROM *PREFIX*quicknotes_tags WHERE ';
 		$sql.= 'id NOT IN (SELECT tag_id FROM *PREFIX*quicknotes_note_tags)';
-		return $this->execute($sql, []);
+		$this->execute($sql, []);
 	}
 }
\ No newline at end of file