public override DbExpression Visit(DbRelationshipNavigationExpression expression)
        {
            Check.NotNull(expression, "expression");

            DbExpression result = expression;

            RelationshipEndMember newFrom;
            RelationshipEndMember newTo;

            VisitRelationshipEnds(expression.NavigateFrom, expression.NavigateTo, out newFrom, out newTo);
            var newNavSource = VisitExpression(expression.NavigationSource);

            if (!ReferenceEquals(expression.NavigateFrom, newFrom)
                ||
                !ReferenceEquals(expression.NavigateTo, newTo)
                ||
                !ReferenceEquals(expression.NavigationSource, newNavSource))
            {
                result = CqtBuilder.Navigate(newNavSource, newFrom, newTo);
            }
            NotifyIfChanged(expression, result);
            return(result);
        }