>>What about the implementation of the 8 relational operators with the same properties as I did describe in the first message ?
>
>List the operators for me, I get Join, Intersection, Difference, and Union. What does your list include.

Look at http://www.utexas.edu/cc/dbms/utinfo/relmod/relmod3.html

The operators are:
UNION
DIFFERENCE
INTERSECTION
PRODUCT
PROJECTION
SELECTION
JOIN
DIVISION

>>What about getting a SQL-select implementation which basicly offers a updatable filtered result, even with joins, so we can use the advantages I mentioned in the first message ?
>
>We have that already with views.

That doesn't have the advantage which I was describing in the original message:
- Changes in the source tables are not reflected inmidiately in the view
- I don't have the benefit of existing indexes of the sourcetables
- the view is independent from the datasource stored as a cursor
- the view is slow because the data must be copied from the datasources
- I can't use the buffering modes NONE and pessimistic row and tablebuffering

Walter,