diff --git a/src/ForeignKeyEditorDelegate.cpp b/src/ForeignKeyEditorDelegate.cpp
index b1c26b7d..e6bd0cad 100644
--- a/src/ForeignKeyEditorDelegate.cpp
+++ b/src/ForeignKeyEditorDelegate.cpp
@@ -11,7 +11,7 @@ class ForeignKeyEditor : public QWidget
     Q_OBJECT
 
 public:
-    ForeignKeyEditor(QWidget* parent = Q_NULLPTR)
+    explicit ForeignKeyEditor(QWidget* parent = Q_NULLPTR)
         : QWidget(parent)
         , tablesComboBox(new QComboBox(this))
         , idsComboBox(new QComboBox(this))
diff --git a/src/RemoteModel.h b/src/RemoteModel.h
index ebe6aaa5..df205687 100644
--- a/src/RemoteModel.h
+++ b/src/RemoteModel.h
@@ -22,7 +22,7 @@ enum RemoteModelColumns
 class RemoteModelItem
 {
 public:
-    RemoteModelItem(RemoteModelItem* parent = nullptr);
+    explicit RemoteModelItem(RemoteModelItem* parent = nullptr);
     ~RemoteModelItem();
 
     QVariant value(RemoteModelColumns column) const;
diff --git a/src/csvparser.cpp b/src/csvparser.cpp
index ff0be680..affc5425 100644
--- a/src/csvparser.cpp
+++ b/src/csvparser.cpp
@@ -128,7 +128,7 @@ CSVParser::ParserResult CSVParser::parse(csvRowFunction insertFunction, QTextStr
     class FieldBufferDealloc
     {
     public:
-        FieldBufferDealloc(CSVRow& row) : m_row(row) {}
+        explicit FieldBufferDealloc(CSVRow& row) : m_row(row) {}
         ~FieldBufferDealloc()
         {
             for(size_t i=0;i<m_row.max_num_fields;i++)
diff --git a/src/sqlitedb.h b/src/sqlitedb.h
index 88dc0d0e..bbc1325c 100644
--- a/src/sqlitedb.h
+++ b/src/sqlitedb.h
@@ -137,7 +137,7 @@ private:
     class NoStructureUpdateChecks
     {
     public:
-        NoStructureUpdateChecks(DBBrowserDB& db) : m_db(db) { m_db.dontCheckForStructureUpdates = true; }
+        explicit NoStructureUpdateChecks(DBBrowserDB& db) : m_db(db) { m_db.dontCheckForStructureUpdates = true; }
         ~NoStructureUpdateChecks() { m_db.dontCheckForStructureUpdates = false; }
 
     private:
diff --git a/src/sqlitetypes.h b/src/sqlitetypes.h
index d31366af..b5160733 100644
--- a/src/sqlitetypes.h
+++ b/src/sqlitetypes.h
@@ -37,7 +37,7 @@ public:
     {
     }
 
-    ObjectIdentifier(QVariant variant)
+    explicit ObjectIdentifier(QVariant variant)
     {
         QStringList str = variant.toStringList();
         m_schema = str.first();
@@ -197,7 +197,7 @@ public:
         CheckConstraintType,
     };
 
-    Constraint(const QString& name = QString())
+    explicit Constraint(const QString& name = QString())
         : m_name(name)
     {
     }
@@ -273,7 +273,7 @@ public:
 class CheckConstraint : public Constraint
 {
 public:
-    CheckConstraint(const QString& expr = QString())
+    explicit CheckConstraint(const QString& expr = QString())
         : m_expression(expr)
     {
     }