【免费】chapter01实践习题2资源-CSDN文库

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C H A P T E R

1

Introdution

Solutions for the Pratie Exerises of Chapter 1

Pratie Exerises

1.1

Answer:

Two disadvantages assoiated with database systems are listed below.

a. Setup of the dat abase system requires more knowledge, money, skills, and

time.

b. The omplexit y of the database may result in poor performane.

1.2

Answer:

a. Exeuting an ation in the

DDL

results in t he reation of an objet in the

database; in ontrast, a programming language type delaration is simply

an abstration used in the prog ram.

b. Database

DDL

s allow onsisteny onstraints to be speied, whih pro-

gramming language type systems generally do not allow. These inlude

domain onstraints and referential integr ity onstraints.

. Database

DDL

s suppor t author ization, giving dierent aess rights to

dierent users. Programming language type systems do not provide suh

protetion (at best, they protet attributes in a lass from being aessed

by methods in another lass).

d. Programming language type systems are usually muh riher than the

SQL

type system. Most dat abases suppor t only basi t ypes suh as dierent

types of numbers and strings, alt hough some databases do suppor t some

omplex types suh as ar rays and objets.

1

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