diff --git a/src/core/Metadata.h b/src/core/Metadata.h
index 7fca99c5..b25d33fb 100644
--- a/src/core/Metadata.h
+++ b/src/core/Metadata.h
@@ -32,7 +32,7 @@ class Metadata : public QObject
     Q_OBJECT
 
 public:
-    Metadata(Database* parent);
+    explicit Metadata(Database* parent);
 
     QString generator() const;
     QString name() const;
diff --git a/src/core/Parser.h b/src/core/Parser.h
index 4d18203c..72c1d75c 100644
--- a/src/core/Parser.h
+++ b/src/core/Parser.h
@@ -35,7 +35,7 @@ class Parser : public QObject
     Q_OBJECT
 
 public:
-    Parser(Database* db);
+    explicit Parser(Database* db);
     bool parse(const QString& filename);
     QString errorMsg();
 
diff --git a/src/core/Uuid.cpp b/src/core/Uuid.cpp
index 4afa7ffb..3302bf2b 100644
--- a/src/core/Uuid.cpp
+++ b/src/core/Uuid.cpp
@@ -17,6 +17,8 @@
 
 #include "Uuid.h"
 
+#include <QtCore/QHash>
+
 const int Uuid::length = 16;
 
 Uuid::Uuid() : m_data(length, 0)
diff --git a/src/core/Uuid.h b/src/core/Uuid.h
index 74b5cf4c..d9714b07 100644
--- a/src/core/Uuid.h
+++ b/src/core/Uuid.h
@@ -25,8 +25,8 @@ class Uuid
 {
 public:
     Uuid();
-    Uuid(bool generate);
-    Uuid(const QByteArray& data);
+    explicit Uuid(bool generate);
+    explicit Uuid(const QByteArray& data);
     QString toBase64() const;
     QByteArray toByteArray() const;
     bool isNull() const;