Questions A

1. Data is to be stored in a structure and to do this a data type must be chosen for each
item of data. Choose a suitable data type from the following list for the data shown in the table:
Logical/Boolean
Alphanumeric/text
Numeric
Date
Name of Field Example Data Data Type
Title (Mr., Mrs., Ms., Dr., etc.)
(Mr, Mrs, Ms, Dr, etc)
alphanumeric (with DOTS)
text (without DOTS)
Phone Number 1378-097-5373
13780975373
alphanumeric (with DASH)
numeric (without DOTS)
Sex M or F logical
Country Botswana text
Date of Birth 01/10/03 date
Years at address 4 numeric
2. Here is a list of examples f data to be put into a structure. Some of this data can have
the logical/Boolean data type and some of it cannot. Complete the following table by placing a
tick in the box next to those items of data could use a logical/Boolean data type.
Items of Data Tick if data type is Logical/Boolean
Driving license (yes or no) o
Sex (M or F) o
Size (S, M, L, XL, XXL)
Airport (PEK, ICN, YNT)
Car registration
Date of purchase
Car Type (Manual/Automatic) o
Fuel Type (diesel or petrol) o

Question B
1. A luxury rental firm keeps the details of the cars it rents out in a table. The structure
and contents of this table are shown below
Reg-Number Make Model Year
DB51 AML Aston Martin DB7 2009
CAB 360M Ferrari 360 Modena 2008
GT X34 FER Ferrari 3555 Spider 2000
MAS 12 Maserati 3200 GTA 2001
FG09 FRT Porsche 911 Turbo 2009
M3 MMM BMW M3 Conv 2010
T433 YTH Jaguar XKB 2009
a. Give the names of TWO fields shown in the above table.
Reg-Number, Year
b. Give the name of the field that should be chosen as the key field.
Reg-Number
c. Explain why the field you have chosen for your answer to part (b) should be chosen as
the key field.
Because its a personal nique number
d. How many records are there in the table?
7
2. Most schools now use database to store details about each pupil. The table shows
some of the field names and data types stored in one pupil database.
Field Data Type
UniquePupilNumber Number
Firstname
Surname Text/Alphanumeric
FirstLineAddress Text/Alphanumeric
SecondLineAddress Text/Alphanumeric
Postcode
LandLineNo Text/Alphanumeric
DateOfBirth Date
FreeSchoolMeals(Y/N)
a. Give the most appropriate data types for the following fields
i. First name Text/Alphanumeric
ii. Postcode Text/Alphanumeric
iii. FreeSchoolMeals (Y/N) Boolean
b. Give the names of THREE other fields that are likely to be used in database
Sex, Nationality, Blood type
c. Explain which field is used as the key field in the database and why such a field is
necessary.
unique pupil number, it can help identify different pupils since other fields of different
pupils might be the same.
d. It is important that the data contained in this database is accurate. Describe
how TWO different errors could occur when data is entered into this database.
Transcription errors - where data copied from forms is misread
Transposition errors - where digits are incorrectly reversed when being entered into a
database.
e. Explain how the errors you have mentioned in part (d) could be detected or
prevented.
You can fix transcription errors by verifying data after you enter it
You can fix transposition errors by adding a check digit at the end of a long number
3.
a. Explain what is meant by a flat file database
one Excel document that has two or more information
b. explain what is meant by a relational database
a database where the data is in two or more tables with relationships
Describe an application where a flat-file database would be suitable
information of all students
4. Databases are two types: flat file and relational
a. Describe TWO differences between a flat-file database and a relational
database
no limit on use, and no data redundancy
b. a dress hire company needs to store details of dresses, customers, and rentals.
They want to store these details in a database. Which type of database d you suggest and
give TWO reasons for your answer.
Relational Database. There would not be data redundancy, and the limitations in using
relational database are less than in using flat files.
Test Yourself
The following notes summarize this topic. The notes are incomplete because they have words
missing. Using the words in the list below, copy out and complete the sentences A to N, underlining
the words that you have inserted. Each word maybe used more than once.
analogue to digital record digital to analogue
foreign real key field Boolean links
redundancy fields relational analogue
alphanumeric digital table
A. Numeric data can be in two forms integer or real
B. Letters and numbers together are called alphanumeric data
C. Logical or Boolean data can have only one of two values: True or False
D. A key field is a piece of data in a database system that is unique to a particular record.
E. All the data relating to a single thing or person is called a record
F. A record consists of many fields
G. A database where the data is held in two or more tables with links established
between them is called a relational database.
H. Flat-file database only contain one table of data
I. Relational database have links called relationships between tables
J. In order to create a relationship a primary key in one table is linked to the same field
called a foreign key in the other table
K. Flat files may suffer from data redundancy where a lot of the data in the table is
repeated
L. An analogue signal from a temperature sensor will need to be converted into a digital
signal before it can be processed by a computer
M. Changing from an analogue to a digital signal is performed using an analogue to digital
converter
N. In order to control a device such as a motor, a digital signal from the computer will
need to be changed into an analogue one and this is done using a digital to analogue converter

REVISION QUESTIONS
1. Here is a sample of the data that is to be stored in an employee database. The data
items shown are the employees' surname, initial, street, postcode, and telephone number
Ahmed, V, 123 The High Street, L23 6DE, 0151-002-1112
Delos, N, 64 North Way, L9 8SS, 0151-002-0011
Doyle, B, 12 Crosby Road, L23 2DF, 0151-002-1212
Carrol, A, 15 Barkfield Drive, L23 7YH, 0151-002-0899
Conway, T, 6 Windle Hey, L23 6ER, 0151-003-0899
Hoch, J 4 Empress Road, L22 7ED, 0151-003-9090
Hoch, J 4 Empress Road, L22 7ED, 0151-003-9090
a. a table is to be set up with four fields. Give field names for the four fields that
would be suitable for the above set of data items
Name, Street Address, Postcode, Telephone Number
b. The person who is designing the database looks at the sample of data above
and notices that there are two people with the same surname and initial who live at the
same address
i. explain why the surname would be an unsuitable key field
Some people might share the same surname, and can easily alter the things.
ii. it is decided that each employee should be given a unique number. What
would be a suitable field name for this field?
User ID
2. A store keeps details abut their customers and their orders in an information handling
system. Part of the data in this system is shown below:
CUSTOMER NUMBER NAME ITEM CODE SIZE COST DELIVERY
2314 J. Hughes 464 Small $290 N
9819 D. Wong 255 Large $767 Y
1311 C. Khled 747 Small $239 N
8276 K. Lee 299 Small $200 Y
9223 F. Smith 108 Large $823 Y
a. Give the names of two key fields used in the above table
Customer Number, Name
b. there is one "Boolean" field in this database, give the name of it
Delivery
c. give the names of two other fields that could be sensibly used in this table other than
customer name, customer address, and customer telephone number
Phone number, Address
d. The store offers free delivery on all items with a cost greater than $200. How
many of the customers shown would qualify for the free delivery?
4
3. Sensors such as temperature, moisture, and light sensors are used to monitor the
growing conditions in a greenhouse
a. explain why computers are not able to read the data directly from these
sensors
because the data is analogue which is different from digital
b. give the name of the device needed to enable the computer to read this data
Analogue to digital converter