About indexes and clusters

Hi everybody,

I have some doubts about these topics. I hope you can help me:

1. I have read that some queries can be solved by just querying the indexes, without actually retrieving data. I don't see this point. Could anyone give me an example?
2. Why it is possible to define an index over several attributes (and the file is ordered taking all of them into account, in the order these attributes are specified), but it is only possible to define a cluster over a single attribute?

Thanks in advance Received on Fri Nov 07 2003 - 10:34:33 CST