Re: First Impressions on Using Alphora's Dataphor
Date: Fri, 27 Aug 2004 05:36:41 GMT
> What is the difference, if any, between UDTs and the domains
> generated by "CREATE DOMAIN" in some RDBMs and, I think, now
> included in the SQL standard?
The CREATE DOMAIN in standard SQL (well, SQL-92, but these things usually don't change much) is a pitiful, neutered non-entity, at least if C J Date is to be believed (and, from what little I know of CREATE DOMAIN, I believe him).
To a crude approximation, the difference is between a full type and a sort of shorthand for a built-in type plus possibly a check constraint which can be dropped even when columns that were defined using the domain name still exist in the database.
-- Jonathan Leffler #include <disclaimer.h> Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/Received on Fri Aug 27 2004 - 07:36:41 CEST