Added list of constraints to the tables page.

Last column shows the full textual definition until I have decided on
a better way to visualize the details.

pglab/ConstraintModel.h

@@ -0,0 +1,51 @@
+#ifndef CONSTRAINTMODEL_H
+#define CONSTRAINTMODEL_H
+
+#include "BaseTableModel.h"
+#include "PgClass.h"
+#include "PgConstraint.h"
+#include <QAbstractTableModel>
+#include <vector>
+
+class PgDatabaseCatalog;
+
+class ConstraintModel : public BaseTableModel {
+	Q_OBJECT
+public:
+
+	enum e_Columns : int {
+		TypeCol,
+		NameCol, ///
+		NsCol, ///
+		SupportingIndexCol,
+		DefinitionCol,
+		colCount };
+
+	explicit ConstraintModel(QObject *parent = nullptr);
+
+	void setData(std::shared_ptr<const PgDatabaseCatalog> cat, const PgClass &table);
+
+
+	// Header:
+	QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
+
+	// Basic functionality:
+	int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+	int columnCount(const QModelIndex &parent = QModelIndex()) const override;
+
+	//QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
+
+protected:
+
+	virtual Oid getType(int column) const override;
+	virtual QVariant getData(const QModelIndex &index) const override;
+
+private:
+	std::shared_ptr<const PgDatabaseCatalog> m_catalog;
+	PgClass m_table;
+
+	using t_Constraints = std::vector<PgConstraint>;
+	t_Constraints m_constraints;
+};
+
+#endif // CONSTRAINTMODEL_H