Lecture 1

Question 1

Why study database management?

Answer 1

• Prevalence

- Advantages over conventional file processing system regarding data independence & the ANSI/SPARC architecture

Question 2

Why are databases better than conventional file processing?

Answer 2

• Spreadsheets don’t scale well with size
• Difficulty linking tables
• slow to run queries
• incorrect results due to denormalized data

Question 3

What are other problems with a File System approach?

Answer 3

• complexity in administration
• data integrity/consistency
• data quality for decision making
• program and data dependence
• insufficient backup & recovery mechanisms
• concurrent access
• data security

Question 4

What are advantages of a database?

Answer 4

• Improved data sharing
• Improved data security
• Better data integration
• Minimized data inconsistency
• Improved data access
• Improved decision making
• Increased end-user productivity

Question 5

What are the 3 layers of the ANSI/SPARC architecture?

Answer 5

External layer (views)
Logical/conceptual layer (tables)
Internal/Physical layer (data structure, disk pages)

Question 6

How does ANSI/SPARC architecture support DBMS characteristics?

Answer 6

• Data independence

- multiple views of the data (security)

Question 7

What is the physical part of the schema of ANSI/SPARC architecture?

Answer 7

• How data is stored on the disc
• data storage structures
• access paths to the data

Question 8

What is the logical part of the schema of ANSI/SPARC architecture?

Answer 8

• how we think the data is organized
• conceptual structure
• integrity constraints

Question 9

What is the external part of the schema of ANSI/SPARC architecture?

Answer 9

• What a user sees of the data

- View is often limited by security

Question 10

What does data independence mean?

Answer 10

each level is independent in the sense that a complete different organization can be used

Question 11

Physical data independence

Answer 11

Physical level can change without having to change the logical level

Question 12

Logical data independence

Answer 12

Logical level can change without having to change the external level

Question 13

What are the main costs of using a DBMS?

Answer 13

• high initial investment
• may need additional hardware
• overhead
• training

Question 14

When may a DBMS be unnecessary?

Answer 14

• Application is simple, well-defined and not expected to change
• stringent real time requirements
• Access to data by multiple users is not needed

Question 15

Data

Answer 15

facts, texts, graphics, sound and video segments that have meaning in the user’s environment

Question 16

Database

Answer 16

an organized collection of logically related data , designed to meet the information needs of an organization
-designed, built and populated for a specific purpose

Question 17

What does CRUD stand for?

Answer 17

Creation
Retrieval
Update or modification
Deletion

*For data to be useful , should be able to perform these core operations

Question 18

DBMS

Answer 18

• Software that supports the creation and maintenance of databases
• Manages the interaction between the end user and the database

Question 19

Components of a database

Answer 19

• Query language processing
• Report generation
• Security & recovery
• Integrity mgmt
• Data & schema definition
• Concurrency control
• Physical access

Question 20

Information

Answer 20

data processed to be useful in decision making

Question 21

Metadata

Answer 21

data that describes the properties or characteristics of other data (e.g. the header of a table)