Chapter 5- DATABASES

Question 1

What is meant by a range check

Answer 1

A range check validates data that falls between two extreme values

Question 2

Explain the term verification

Answer 2

Verification is a check that data is correct, compared with the source or duplicate file

Question 3

What is a check digit

Answer 3

An extra digit added to a data item produced by an algorithm or calculations

Question 4

Surname

Answer 4

Length, type

Question 5

Date of birth

Answer 5

Length, range

Question 6

Gender

Answer 6

Length, type

Question 7

Credit limit

Answer 7

Number, range

Question 8

Telephone number

Answer 8

Length, type

Question 9

Password

Answer 9

Length, type

Question 10

Define the term data redundancy

Answer 10

The unnecessary repetition of data

Question 11

Explain how data redundancy affects this table

Answer 11

City names are repeated

Question 12

Explain what problems could occur due to data redundancy

Answer 12

Alternative spellings might be used so data is not found

Question 13

Explain how the data could be stored to eliminate this problem

Answer 13

Store city names and addresses in separate tables

Question 14

Explain what DBMS is

Answer 14

Database management software that controls the setting up and interrogation of a database

Question 15

What is a database

Answer 15

A store of persistent and organised data

Question 16

What is a flat file database

Answer 16

A flat file database consists of only one table

Question 17

What is a relational database

Answer 17

Data stored in tables, linked in key fields with each row the same structure and size

Question 18

Describe four features of a typical DBMS

Answer 18

Forms
Reports
Queries
Tables

Question 19

Describe the difference between an entity and a table

Answer 19

An entity is a real world object, a table is a data structure that holds data about an entity

Question 20

Describe two ways in which a query can be constructed

Answer 20

QBE, a visual interface or programmed query language

Question 21

Define the term validation

Answer 21

Validation is a check on data as it is input carried out by a software or the computer