Re: Relational vs. PICK/Object DBMS

From: Neo <neo55592_at_hotmail.com>
Date: 25 Apr 2004 10:54:25 -0700
Message-ID: <4b45d3ad.0404250954.5bcf60f8_at_posting.google.com>

> 1) Suppose you have a bunch of attributes that describes the entities in
> your database. Suppose any attribute is optional for any entity.
>
> a) For a given set of attributes
> - find all the entities that for EVERY attribute in the given set
> have at least one value.
> - also find the values of the given attributes
>
> b) For a given entity
> - find all the attributes that have at least one value for the given entity
> - also find the values of the attributes for the given entity

Does the following data, queries and results demo your question?

wig1's color is red.
wig2's color is red, green AND texture is soft AND material is nylon.
wig3's texture is soft AND material is jute.

coat1's color is red.

coat2's texture is soft AND material is cotton. coat3's color is green AND texture is smooth, supple.

Given the attribute set {color, texture} Query a1 returns: wig2 and coat3.
Query a2 returns:
  wig2's color is red, green AND texture is soft.   coat3's color is green AND texture is smooth, supple.

Query b1)

Given wig1, returns wig1's color is red.
Given wig2, returns wig2's color is red, green AND texture is soft.
Given wig3, returns wig3's texture is soft.

If the above doesn't demo your question, can you modifiy it? Received on Sun Apr 25 2004 - 19:54:25 CEST