Some work on multicolumn sort.

src/core/messagesmodel.cpp

@@ -39,8 +39,8 @@ MessagesModel::MessagesModel(QObject *parent)
   // via model, but via DIRECT SQL calls are used to do persistent messages.
   setEditStrategy(QSqlTableModel::OnManualSubmit);
   setTable(QSL("Messages"));
-
   setRelation(MSG_DB_FEED_INDEX, QSqlRelation("Feeds", "custom_id", "title"));
+
   loadMessages(nullptr);
 }
 
@@ -48,6 +48,10 @@ MessagesModel::~MessagesModel() {
   qDebug("Destroying MessagesModel instance.");
 }
 
+QString MessagesModel::orderByClause() const {
+  return QSqlRelationalTableModel::orderByClause();
+}
+
 void MessagesModel::setupIcons() {
   m_favoriteIcon = qApp->icons()->fromTheme(QSL("mail-mark-important"));
   m_readIcon = qApp->icons()->fromTheme(QSL("mail-mark-read"));

src/core/messagesmodel.h

@@ -44,6 +44,8 @@ class MessagesModel : public QSqlRelationalTableModel {
     explicit MessagesModel(QObject *parent = 0);
     virtual ~MessagesModel();
 
+    QString orderByClause() const;
+
     // Model implementation.
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
     QVariant data(int row, int column, int role = Qt::DisplayRole) const;

src/core/messagesproxymodel.cpp

@@ -72,7 +72,7 @@ bool MessagesProxyModel::lessThan(const QModelIndex &left, const QModelIndex &ri
   Q_UNUSED(left)
   Q_UNUSED(right)
 
-  // NOTE: Porovnání se provádí již při dotazu v databázi, netřeba řešit zde.
+  // NOTE: Comparisons are done by SQL servers itself, not client-side.
   return false;
 }
 

src/gui/messagesview.cpp

@@ -563,4 +563,6 @@ void MessagesView::onSortIndicatorChanged(int column, Qt::SortOrder order) {
   // Repopulate the shit.
   m_sourceModel->sort(column, order);
   emit currentMessageRemoved();
+
+  qDebug("Current order by clause is '%s'.", qPrintable(m_sourceModel->orderByClause()));
 }