Re: Difference between catalog and metadata?

"Digital Puer" <digital_puer_at_hotmail.com> wrote in message news:c4abc357-ff00-4929-883e-53331c3f1c49_at_p36g2000prn.googlegroups.com...
> I'm doing a little research into database metadata for various
> products like DB2, Oracle, SQL Server, and MySQL. I want
> to learn about where information on tables and views are stored.
>
> What is the difference between the system catalog and
> metadata? Is one a superset of the other?
>
> Which one of them contains logical and physical information
> on the tables and views (e.g. how they are partitioned,
> the schemas, etc.)?
>
> Is there a SQL / ANSI standard on what information should
> be stored in the catalog / metadata?

Metadata is simply data whose subject matter is data. The system catalog is metadata, but metadata could exist in other forms as well.

DB2, Oracle, and SQL server all came into being before there was a standard form for the metadata that describes database objects. Shortly after the SQL standard
was set up for system tables, all these products included views on their system tables that allow a user to see this data in standard form. I do not know if the various products have actually changed their base system tables to conform to the standard. Received on Wed Jul 22 2009 - 05:22:43 CEST