##
CSE3330/5330 Homework #5

Due on Thursday April 29, before midnight

Worth 3.33% of the final grade

*(40 points)* Suppose we have a database for an investment firm, consisting of the
following attributes:
**(B)** Broker
**(O)** Office of a broker
**(I)** Investor
**(S)** Stock
**(Q)** Quantity of stock owned by an investor
**(D)** Dividend paid by a stock.

with the following functional dependencies:

*(15 points)* Find a key for the relation schema
.
*(15 points)* Give a lossless-join decomposition into BCNF of the schema .
*(10 points)* Give a lossless-join, dependency preserving decomposition into 3NF of the schema .

*(60 points)*
Consider the relation schema
that satisfies the
following functional dependencies:

*(10 points)* Show that the decomposition of into and
is a lossless-join decomposition but not a dependency preserving.
*(10 points)* Show using a counterexample that the decomposition of into and
is not a lossless-join decomposition.
*(20 points)* Give a lossless-join decomposition into BCNF of the schema .
*(20 points)* Give a lossless-join, dependency preserving decomposition into 3NF of the schema .

Last modified: 04/27/10 by Leonidas Fegaras