Re: Other attributes besides type,precision,scale

Following script for an experimental db (XDb3) models companies/vendors with 0-to-many websites and websites with 0-to-many IP Addresses. Sample queries at end.

// Create types.

(CREATE type inst *company)
(CREATE type inst *vendor)
(CREATE type inst *website)
(CREATE type inst *ipAddr)

// Create a company/vendor that doesn't have a website.
(CREATE company inst *compaq

      & vendor inst it)

// Create a company/vendor that has a website.
(CREATE company inst *dell

      & vendor inst it
      & it website *www.dell.com)

// Create a company/vendor that has two websites
// the first of which has two IP addresses.
(CREATE company inst *oracle

      & vendor inst it
      & it website (CREATE website inst *www.oracle.com
                         & it ipAddr +66.123.45.33
                         & it ipAddr +66.123.45.34)
      & it website *www.db.com)

// Find vendors that have a website.
// Finds dell and oracle.

(SELECT vendor inst *

      & * website)

// Find companies whose website's ipAddr is 66.123.45.33.
// Finds oracle.

(SELECT company inst *

      & * website (* ipAddr 66.123.45.33))

// Find oracle's websites' ipAddrs.
// Finds 66.123.45.33 and 66.123.45.34.
(SELECT (oracle website *) ipAddr *) Received on Thu Mar 31 2005 - 04:17:43 CEST