Put color on own database. Umm.. Any relationship placed on the note controller.

db/notemapper.php

@@ -3,6 +3,7 @@ namespace OCA\QuickNotes\Db;
 
 use OCP\IDb;
 use OCP\AppFramework\Db\Mapper;
+use OCP\AppFramework\Db\DoesNotExistException;
 
 class NoteMapper extends Mapper {
 
@@ -20,4 +21,12 @@ class NoteMapper extends Mapper {
 		return $this->findEntities($sql, [$userId]);
 	}
 
+	public function colorIdCount($colorid) {
+		$sql = 'SELECT COUNT(*) as `count` FROM *PREFIX*quicknotes WHERE color_id = ?';
+		$result = $this->execute($sql, [$colorid]);
+		$row = $result->fetch();
+		$result->closeCursor();
+		return $row['count'];
+	}
+
 }