The script below models the following requirements using an
experimental db (XDb3). The equivalent can be performed with an RMDB
using nested relations and generic modelling.

- A person has 0 to may diaries.
- A diary contains 0 to many days.
- A day has 0 to many events.
- An event has a start time.
- An event has 0 to many participants.

// Create directoy items to organize things.
(CREATE dir item *person)
(CREATE dir item *diary)
(CREATE dir item *day)
(CREATE dir item *event)
(CREATE dir item *time)
(CREATE dir item *participant)

// Create persons john, mary and bob.
(CREATE person inst *john)
(CREATE person inst *mary)
(CREATE person inst *bob)

// Log lunch with mary at 12PM on 2/25/05 in john's work diary.
(CREATE john diary *work day +2/25/05 event +lunch time +1200 )
(CREATE john diary work day +2/25/05 event +lunch participant mary)

// Log meeting with bob at 1PM on 2/25/05 in john's work diary.
(CREATE john diary work day +2/25/05 event +meeting time +1300)
(CREATE john diary work day +2/25/05 event +meeting participant bob)

// Log golf w/ mary and bob at 9AM on 2/26/05 in john's personal diary.
(CREATE john diary *personal day +2/26/05 event +golf time +900)
(CREATE john diary personal day +2/26/05 event +golf participant mary)
(CREATE john diary personal day +2/26/05 event +golf participant bob)

// Find all events in john's work diary for 2/25/05.
// Finds lunch and meeting.
(SELECT john diary work day 2/25/05 event *)

// Find what are mary and bob participants of.
// Finds golf on 2/26/05 logged in john's personal diary.
(SELECT * participant mary & * participant bob)

Neo wrote:
Don't multi-post!

--
Lee Fesperman, FFE Software, Inc. (http://www.firstsql.com)
================================================== ============
* The Ultimate DBMS is here!
* FirstSQL/J Object/Relational DBMS (http://www.firstsql.com)