# Relational vs. PICK/Object DBMS

Date: Tue, 20 Apr 2004 19:17:24 +0300

Message-ID: <40854c6a$1_at_post.usenet.com>

Periodical discussions about the relational model/DBMS versus PICK or object
model/DBMS take place in this newsgroup.
I have some training in the relational model, but none in object/PICK like
**DBMS.
**

I would like to know which model/DBMS perform better (in terms of
programmers productivity, system requirements, etc.) on the following
problems (stated in terms of relational model) :

1)Been given the domains {A,A1,A2,...,An}, with large n and the following database schema:

- for all i in 1..n, Ri(A,Ai) is a base relation
- for all i in 1..n, A is a candidate key for the relation Ri

answer the questions:

a) for {i1,i2,...,ip} given , find R(A,Ai1,Ai2,...,Aip) with the constraints
R(A,Aik) = Rik(A,Aik) for all k in 1..p, R is minimal.
b) for a in A given, find R(A,Ai1,Ai2,...,Aip) with the constraints:

- R(A,Aik) = Rik(A,Aik) for all k in 1..p
- {Ai1,...,Aip} is maximal
- R is minimal 2) Let P(A) be the power set of domain A for any domain A. Been given the domains {A,B,C} and the database schema R1(P(A),P(B)), R2(P(B),P(C)) answer the question: find R(P(A),P(B),P(C)) with the contstraints: - R(P(A),P(B))=R1(P(A),P(B)) - R(P(B),P(C))=R2(P(B),P(C)) - R minimal

Note:

a) No NULLs are allowed

b) R(X1,X2,...,Xp) is the projection of R on the attributes (X1,...,Xp)

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

- Usenet.com - The #1 Usenet Newsgroup Service on The Planet! *** http://www.usenet.com Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=