SOLUTIONS TO REVIEW QUESTIONS
%tf %tf %tf
%tf AND EXERCISES
%tf
FOR PART 1 – BACKGROUND (CHAPTERS 1 – 3)
%tf %tf %tf %tf %tf %tf %tf %tf
,Database %tfSystems: %tfInstructor’s %tfGuide %tf-
%tfPart %tfIII
Solutions %tfto %tfReview %tfQuestions %tfand %tfExercises
Chapter %tf1 % t f Introduction %tfto %tfDatabases .................................................................................. 3
Chapter %tf2 %t f Database %tfEnvironment ......................................................................................... 7
Chapter %tf3 %tf Database %tfArchitectures %tfand %tfthe %tfWeb ............................................................ 11
2
,Database %tfSystems: %tfInstructor’s %tfGuide %tf-
%tfPart %tfIII
Chapter 1 Introduction to Databases
Review Questions
1.1 List four examples of database systems other than those listed in Section 1.1.
Some examples could be:
• A system that maintains component part details for a car manufacturer;
• An advertising company keeping details of all clients and adverts placed with them;
• A training company keeping course information and participants’ details;
• An organization maintaining all sales order information.
1.2 Discuss each of the following terms:
Data For end users, this constitutes all the different values connected with the
various objects/entities that are of concern to them. See also Section 1.3.4.
Database See Section 1.3.1
Database Management System See Section 1.3.2
Database Application Program See Section 1.3.3
Data Independence This is essentially the separation of underlying file structures from the
programs that operate on them, also called program-data independence. See
also Sections 1.2.2 and 1.3.1.
Security The protection of the database from unauthorized users, which may involve
passwords and access restrictions. See also Section 1.6.
Integrity The maintenance of the validity and consistency of the database by use of
particular constraints that are applied to the data. See also Section 1.6.
Views These present only a subset of the database that is of particular interest to a
user. Views can be customized, for example, field names may change, and
they also provide a level of security preventing users from seeing certain
data. See also Section 1.3.3.
1.3 Describe the approach taken to the handling of data in the early file-based systems. Discuss the
disadvantages of this approach.
Focus was on applications for which programs would be written, and all the data required would
be stored in a file or files owned by the programs. See also Section 1.2.
Clearly, each program was responsible for only its own data, which could be repeated in other
program’s data files. Different programs could be written in different languages, and would not be
able to access another program’s files. This would be true even for those programs written in the
same language, because a program needs to know the file structure before it can access it. See also
Section 1.2.2.
1.4 Describe the main characteristics of the database approach and contrast it with the file-based
approach.
3
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4
%tf %tf %tf
%tf AND EXERCISES
%tf
FOR PART 1 – BACKGROUND (CHAPTERS 1 – 3)
%tf %tf %tf %tf %tf %tf %tf %tf
,Database %tfSystems: %tfInstructor’s %tfGuide %tf-
%tfPart %tfIII
Solutions %tfto %tfReview %tfQuestions %tfand %tfExercises
Chapter %tf1 % t f Introduction %tfto %tfDatabases .................................................................................. 3
Chapter %tf2 %t f Database %tfEnvironment ......................................................................................... 7
Chapter %tf3 %tf Database %tfArchitectures %tfand %tfthe %tfWeb ............................................................ 11
2
,Database %tfSystems: %tfInstructor’s %tfGuide %tf-
%tfPart %tfIII
Chapter 1 Introduction to Databases
Review Questions
1.1 List four examples of database systems other than those listed in Section 1.1.
Some examples could be:
• A system that maintains component part details for a car manufacturer;
• An advertising company keeping details of all clients and adverts placed with them;
• A training company keeping course information and participants’ details;
• An organization maintaining all sales order information.
1.2 Discuss each of the following terms:
Data For end users, this constitutes all the different values connected with the
various objects/entities that are of concern to them. See also Section 1.3.4.
Database See Section 1.3.1
Database Management System See Section 1.3.2
Database Application Program See Section 1.3.3
Data Independence This is essentially the separation of underlying file structures from the
programs that operate on them, also called program-data independence. See
also Sections 1.2.2 and 1.3.1.
Security The protection of the database from unauthorized users, which may involve
passwords and access restrictions. See also Section 1.6.
Integrity The maintenance of the validity and consistency of the database by use of
particular constraints that are applied to the data. See also Section 1.6.
Views These present only a subset of the database that is of particular interest to a
user. Views can be customized, for example, field names may change, and
they also provide a level of security preventing users from seeing certain
data. See also Section 1.3.3.
1.3 Describe the approach taken to the handling of data in the early file-based systems. Discuss the
disadvantages of this approach.
Focus was on applications for which programs would be written, and all the data required would
be stored in a file or files owned by the programs. See also Section 1.2.
Clearly, each program was responsible for only its own data, which could be repeated in other
program’s data files. Different programs could be written in different languages, and would not be
able to access another program’s files. This would be true even for those programs written in the
same language, because a program needs to know the file structure before it can access it. See also
Section 1.2.2.
1.4 Describe the main characteristics of the database approach and contrast it with the file-based
approach.
3
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%tfPart %tfIII
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4
