Re: Relational Algebra Operators

From: Paul Wagner <wagner_at_cs.umn.edu>
Date: 25 Mar 1999 02:32:03 GMT
Message-ID: <7dc773$e36$1@news1.tc.umn.edu>

Oracle does support all of these relational algebra (R.A.) operations in one way or another. The Oracle SQL SELECT statement can do many things

(including R.A. select) - it can filter rows (R.A. select), filter columns 
(R.A. project), or combine information from multiple relational tables 
(R.A. product if done combining all rows from the first table with all

rows from the second tablein, R.A. join if combining rows according to a meaningful join condition. Oracle has INTERSECT, UNION, and MINUS operators which support R.A. intersect, union and difference, respectively. R.A. Divide is not present as its own operator, but can be implemented as a series of R.A. operations including minus, project, and times/product.

Paul

In article <36F996A5.7F30_at_smip.com>, Gary C. New <gnew_at_smip.com> wrote:
>I'm trying to find out of the following relational functions which are
>supported by Oracle: SELECT, PROJECT, JOIN, INTERSECT, UNION,
>DIFFERENCE, PRODUCT, and DIVIDE? After browsing through Oracle8i's
>latest doc's I was only able to verify that it supports the SELECT
>function.
>
>This can't be the only relational algebra operator of those listed above
>that is supported, right?

--

*    *    *    *    *    *    *    *    *    *    *    *    *    *    *    *
* Paul J. Wagner                School   - wagner_at_cs.umn.edu               *
* Computer Science Department   Work     - wagnerp_at_uwstout.edu             *
* University of Minnesota                                                  *
*    *    *    *    *    *    *    *    *    *    *    *    *    *    *    *

Received on Wed Mar 24 1999 - 20:32:03 CST