Deveel.Data.Sql.Query.SortNode.SortNode C# (CSharp) Method

        public SortNode(IQueryPlanNode child, ObjectName[] columnNames, bool[] ascending)
            : base(child)
        {
            // How we handle ascending/descending order
            // ----------------------------------------
            // Internally to the database, all columns are naturally ordered in
            // ascending order (start at lowest and end on highest).  When a column
            // is ordered in descending order, a fast way to achieve this is to take
            // the ascending set and reverse it.  This works for single columns,
            // however some thought is required for handling multiple column.  We
            // order columns from RHS to LHS.  If LHS is descending then this will
            // order the RHS incorrectly if we leave as is.  Therefore, we must do
            // some pre-processing that looks ahead on any descending orders and
            // reverses the order of the columns to the right.  This pre-processing
            // is done in the first pass.

            int sz = ascending.Length;
            for (int n = 0; n < sz - 1; ++n) {
                if (!ascending[n]) {    // if descending...
                    // Reverse order of all columns to the right...
                    for (int p = n + 1; p < sz; ++p) {
                        ascending[p] = !ascending[p];
                    }
                }
            }

            ColumnNames = columnNames;
            Ascending = ascending;
        }