D A T A B A S E S Y S T E M S
Database Fundamentals & DBMS
Concepts
Complete Exam Revision Notes with Worked Examples and Practice Questions
Part 1 of the Database Systems Revision Series
Covers: DBMS basics, file systems vs DBMS, three-schema architecture, data models, database
languages, DBMS architecture, database life cycle
Includes: 15 practice questions with full answers, glossary, one-page revision summary
, Database Fundamentals & DBMS Concepts
What This Guide Covers
Use this page as a map of the unit. Each section ends with the points examiners ask about most
often.
# Section Why it matters in exams
1 Introduction: data, information, database, DBMS Definitions are asked almost every year
2 File-based systems vs the database approach Classic compare-and-contrast question
3 Characteristics of the database approach Often a list-and-explain question
4 Components of a database system Short answer, 5 components
5 People in database systems Roles of DBA, designers, users
6 Three-schema architecture and data High-mark, diagram-based question
independence
7 Schemas and instances Short definitions with example
8 Data models Comparison table
9 Database languages: DDL, DML, DCL, TCL Identify the category of a statement
10 DBMS architecture and components Explain components and tiers
11 Advantages and disadvantages of DBMS Discuss / justify questions
12 Database system development life cycle List and explain stages
13 Glossary of key terms Quick definitions
14 Practice questions with answers Test yourself
15 One-page revision summary Last-minute review
How to use this guide
Read sections 1 to 12 once, attempt the practice questions in section 14 without looking at the
answers, then use section 15 the night before the exam.
Where your lecturer uses different terminology or emphasis, add your own notes in the margins.
Page 2
, Database Fundamentals & DBMS Concepts
1. Introduction
1.1 Data and information
Data is a collection of raw facts that have not yet been processed to give them meaning.
Information is data that has been processed, organized, or put in context so that it is useful for
making decisions.
Data (raw facts) Information (processed, meaningful)
45, 62, 78, 50 The average mark for the class is 58.75
Wanjiru, 21, Nairobi Wanjiru is a 21-year-old student from Nairobi
Sales: 1200, 800, 1500 Total sales this week were 3,500, with Wednesday
the best day
1.2 What is a database?
A database is an organized collection of logically related data, stored so that it can be easily
accessed, managed, and updated. A database usually has these properties:
• It represents some part of the real world, often called the miniworld or universe of discourse
(for example, a university, a bank, or a shop).
• It is a logically coherent collection of data with some inherent meaning. A random mix of data
is not a database.
• It is designed, built, and populated for a specific purpose and for an intended group of users
and applications.
1.3 What is a DBMS?
A Database Management System (DBMS) is software that lets users define, create, maintain, and
control access to a database. It sits between the users or application programs and the stored data.
• Defining a database means specifying the data types, structures, and constraints of the data.
• Constructing a database means storing the data on a medium controlled by the DBMS.
• Manipulating a database means querying it, updating it, and generating reports.
• Sharing a database means allowing many users and programs to access it at the same time.
Common DBMS products include MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server,
SQLite, and MongoDB (a NoSQL system).
1.4 Database system
The term database system refers to the database together with the DBMS software and the
application programs that use it:
Database system = Database + DBMS software + Application programs
Page 3
Database Fundamentals & DBMS
Concepts
Complete Exam Revision Notes with Worked Examples and Practice Questions
Part 1 of the Database Systems Revision Series
Covers: DBMS basics, file systems vs DBMS, three-schema architecture, data models, database
languages, DBMS architecture, database life cycle
Includes: 15 practice questions with full answers, glossary, one-page revision summary
, Database Fundamentals & DBMS Concepts
What This Guide Covers
Use this page as a map of the unit. Each section ends with the points examiners ask about most
often.
# Section Why it matters in exams
1 Introduction: data, information, database, DBMS Definitions are asked almost every year
2 File-based systems vs the database approach Classic compare-and-contrast question
3 Characteristics of the database approach Often a list-and-explain question
4 Components of a database system Short answer, 5 components
5 People in database systems Roles of DBA, designers, users
6 Three-schema architecture and data High-mark, diagram-based question
independence
7 Schemas and instances Short definitions with example
8 Data models Comparison table
9 Database languages: DDL, DML, DCL, TCL Identify the category of a statement
10 DBMS architecture and components Explain components and tiers
11 Advantages and disadvantages of DBMS Discuss / justify questions
12 Database system development life cycle List and explain stages
13 Glossary of key terms Quick definitions
14 Practice questions with answers Test yourself
15 One-page revision summary Last-minute review
How to use this guide
Read sections 1 to 12 once, attempt the practice questions in section 14 without looking at the
answers, then use section 15 the night before the exam.
Where your lecturer uses different terminology or emphasis, add your own notes in the margins.
Page 2
, Database Fundamentals & DBMS Concepts
1. Introduction
1.1 Data and information
Data is a collection of raw facts that have not yet been processed to give them meaning.
Information is data that has been processed, organized, or put in context so that it is useful for
making decisions.
Data (raw facts) Information (processed, meaningful)
45, 62, 78, 50 The average mark for the class is 58.75
Wanjiru, 21, Nairobi Wanjiru is a 21-year-old student from Nairobi
Sales: 1200, 800, 1500 Total sales this week were 3,500, with Wednesday
the best day
1.2 What is a database?
A database is an organized collection of logically related data, stored so that it can be easily
accessed, managed, and updated. A database usually has these properties:
• It represents some part of the real world, often called the miniworld or universe of discourse
(for example, a university, a bank, or a shop).
• It is a logically coherent collection of data with some inherent meaning. A random mix of data
is not a database.
• It is designed, built, and populated for a specific purpose and for an intended group of users
and applications.
1.3 What is a DBMS?
A Database Management System (DBMS) is software that lets users define, create, maintain, and
control access to a database. It sits between the users or application programs and the stored data.
• Defining a database means specifying the data types, structures, and constraints of the data.
• Constructing a database means storing the data on a medium controlled by the DBMS.
• Manipulating a database means querying it, updating it, and generating reports.
• Sharing a database means allowing many users and programs to access it at the same time.
Common DBMS products include MySQL, PostgreSQL, Oracle Database, Microsoft SQL Server,
SQLite, and MongoDB (a NoSQL system).
1.4 Database system
The term database system refers to the database together with the DBMS software and the
application programs that use it:
Database system = Database + DBMS software + Application programs
Page 3
