Modify QSqlQueryModel roleNames

QSqlQueryModel::roleNames was exposing the default QAbstractItemModel
roles. Only "display" role makes sense because it's a read-only model
and it is not providing any other data information.

[ChangeLog][Important Behavior Changes] The names of the roles
returned by QSqlQueryModel::roleNames now only include a name for the
Qt::DisplayRole. Previously all the roles names of QSqlQueryModel
were returned.

Task-number: QTBUG-60857
Change-Id: Ib18aa0e7083a828648767d700c5af05b6aa84f4f
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

src/sql/models/qsqlquerymodel.cpp

@@ -212,6 +212,30 @@ bool QSqlQueryModel::canFetchMore(const QModelIndex &parent) const
     return (!parent.isValid() && !d->atEnd);
 }
 
+/*!
+    \since 5.10
+    \override
+
+    Returns the model's role names.
+
+    Qt defines only one role for the QSqlQueryModel:
+
+    \table
+    \header
+    \li Qt Role
+    \li QML Role Name
+    \row
+    \li Qt::DisplayRole
+    \li display
+    \endtable
+*/
+QHash<int, QByteArray> QSqlQueryModel::roleNames() const
+{
+    return QHash<int, QByteArray> {
+        { Qt::DisplayRole, QByteArrayLiteral("display") }
+    };
+}
+
 /*! \internal
  */
 void QSqlQueryModel::beginInsertRows(const QModelIndex &parent, int first, int last)

src/sql/models/qsqlquerymodel.h

@@ -86,6 +86,8 @@ public:
     void fetchMore(const QModelIndex &parent = QModelIndex()) Q_DECL_OVERRIDE;
     bool canFetchMore(const QModelIndex &parent = QModelIndex()) const Q_DECL_OVERRIDE;
 
+    QHash<int, QByteArray> roleNames() const override;
+
 protected:
     void beginInsertRows(const QModelIndex &parent, int first, int last);
     void endInsertRows();