Joining data tables and system tables
Date: 27 Dec 2002 07:50:29 -0800
Can I express this using purely relational operators?:
I want to list all relations (tables) in my database, together with the total number of tuples (rows) in each relation.
I can get the list of relations from the system catalog. I can use an COUNT aggregate to count the numnber of rows in a given relation.
But how do I link the two so the DBMS does the hard work of counting each table for me? I know how to use procedural code, "dynamic SQL" or other tricks for specific DBMSs; I'm more interested from a theoretical viewpoint.
I don't think it's possible in SQL.
Is it possible in general relational algebra? Is it possible in Dataphor or other "next generation" RDBMSs?
It would seem quite a reasonable thing to want to do.
Paul. Received on Fri Dec 27 2002 - 16:50:29 CET