New column page

Shows SQL for columns ALTER TABLE ... [ADD|DROP] COLUMN combines a selection
of multiple columns into a single alter table.
Show collation in list of columns.

(order of columns isn't what is should be but that should maybe be fixed
by a generic column selection and ordering mechanism that knows what the
default sort should be)

pglab/ColumnPage.h

@@ -0,0 +1,42 @@
+#ifndef COLUMNPAGE_H
+#define COLUMNPAGE_H
+
+#include "PgClass.h"
+#include <QSplitter>
+#include <memory>
+#include <optional>
+
+
+class QTableView;
+class SqlCodePreview;
+class PgDatabaseCatalog;
+class ColumnTableModel;
+class CustomFilterSortModel;
+class QItemSelection;
+class QAbstractItemModel;
+
+class ColumnPage : public QSplitter
+{
+	Q_OBJECT
+public:
+	explicit ColumnPage(QWidget *parent = nullptr);
+
+	void setData(std::shared_ptr<const PgDatabaseCatalog> cat, const std::optional<PgClass> &cls);
+	//void setFilter(const std::optional<PgClass> &cls);
+signals:
+
+public slots:
+
+private:
+	QTableView *m_tableView = nullptr;
+	SqlCodePreview *m_definitionView = nullptr;
+	ColumnTableModel *m_columnModel = nullptr;
+	CustomFilterSortModel *m_sortFilterProxy = nullptr;
+	std::shared_ptr<const PgDatabaseCatalog> m_catalog;
+	std::optional<PgClass> m_Class;
+
+private slots:
+	void tableView_selectionChanged(const QItemSelection &selected, const QItemSelection &deselected);
+};
+
+#endif // COLUMNPAGE_H