Re: Multidimensional query involving ranges

I heared of a method that uses a "Z"-curve. If you have two integer columns then you create an index on the value that you get when you interwaeve the values of the two columns bitwise. If you increase this value then you traverse the 2dimensional plane in shapes that look like the letter "Z".

Lookup is done by using this index, but it requires more than a simple range scan. Basically the problem is, that even though the Z-curve has a tendency to cover rectangular areas, it still may leave the area of interest. At the end you need multiple range scans and to compute these ranges is not trivial.

I don't think this is available in any commercial database. Maybe this method is logically equivalent to what Paul is talking about. Received on Thu Jun 07 2001 - 19:05:00 CEST