Re: On what OLAP can and what OLAP can't - A little problem

Hi Jan, thanks,

> Do you really want to repeat in
> it the information for each ItemB for a Name for each ItemA for that
> Name? Why so much redundancy?

It is a perfectly legal request a(ny) user can make. The user want to list the items and the total amount. But the point is not this. The point is to find a general method to deal with any request of report. It's an abstract problems which is not related with semantic value of items. It must only depend on table structures, relationships, aggregate function properties and fields involved in report.

The point is not to discuss this specific example. Examples are uuseful to fix ideas or find counterexamples. This is a "Theory" group. So I am expecting abstraction and a systematic method to build these queries.

> I can of course give you the SQL statement to

You may have missed the preceding post where such a statement has already been provided. For readers' convenience I have repacked this in a new thread:

http://groups.google.it/group/comp.databases.theory/browse_frm/thread/538735631f141027?hl=it

Please respond there so that other can follow.

I >suggest you first give
> what you think is the content of your report in the example you gave.

That's the point. Content is unimportant. What matters are only formal the properties of involved objects.
The input of the problem are:

• Tables (in abstract sense, as a list of field) and a list of their field including datatype
• Relationships
• Structure (list of fields) of the report with properties of involved functions:
  • Function is aggregate: Yes/No
  • Function is sensitive to replication (eg. sum): Yes/no

> -- Jan Hidders
Received on Thu Sep 14 2006 - 16:57:48 CEST