# Relational vs. PICK/Object DBMS

From: x <x-false_at_yahoo.com>
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

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)

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Received on Tue Apr 20 2004 - 18:17:24 CEST

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