9 - Databases

Question 1

What is data? [2]

Answer 1

• refers to the individual pieces of information that are stored
• information about something

Question 2

What is a base? [2]

Answer 2

• signifies that it is the foundation or platform
• where data is stored and managed

Question 3

What are examples of data and what can it include? [2]

Answer 3

• someone’s age, someone’s salary, etc
• can include: text, pictures, numbers, multimedia, etc

Question 4

What is a database? [3]

Answer 4

• structured collection of data that allows people to extract, add, delete and update information in a way that meets their needs

Question 5

Where are databases used? [3]

Answer 5

• to store information about people
• to store information about things
• to store information about events

Question 6

What are examples of information that might be stored about people? [2]

Answer 6

• patients in a hospital
• pupils at a school

Question 7

What are examples of information that might be stored about things? [2]

Answer 7

• cars to be sold
• books in a library

Question 8

What are examples of information that might be stored about events? [2]

Answer 8

• hotel bookings
• results of races

Question 9

What are flat files? [2]

Answer 9

• a simple table consisting of fields in columns and records in rows

Question 10

Why are flat files called flat? [2]

Answer 10

• they store data in a simple, plain text format without any complex structure
• the data is organised in a straightforward manner

Question 11

How is data organised in a flat file? [2]

Answer 11

• seperated by commas or tabs
• each line represents a single record

Question 12

What are examples of flat files? [3]

Answer 12

• notepad
• microsoft excel
• microsoft word

Question 13

What are the issues related to flat files? [3]

Answer 13

• data inconsistency (not updated)
• miscommunication
• takes up too much storage

Question 14

What are the solutions to these issues? [6]
(3 reasons + explanations)

Answer 14

• data is stored centrally and accessed by different applications
• changes made by one application is reflected in another application
• access rights and privileges are maintained so you can control who can access, edit and modify data

Question 15

What are the two things a table consists of? [2]

Answer 15

• fields
• records

Question 16

What is a field + example? [2]

Answer 16

• one type of information
• e.g. name

Question 17

What is a record + example? [2]

Answer 17

• details
• e.g. name, age, salary together

Question 18

What does a table contain data about? [3]

Answer 18

one type of item, person or event + given a meaningful name

Question 19

What does a record within a table contain data about? [3]

Answer 19

a single item, person or event

Question 20

What are the data types used in databases? [6]

Answer 20

• text/alphanumeric
• character
• boolean
• integer
• real
• data/time

Question 21

Give examples of each data type used in databases. [6]

Answer 21

• text: Sumridhi
• character: S
• boolean: Yes/No
• integer: 16
• real: 11.23
• date/time: 23/06/09

Question 22

What does a data type classify? [2]

Answer 22

• how the data is stored and displayed
• the operations that can be performed on the stored value

Question 23

What is a real data type? [1]

Answer 23

a decimal number

Question 24

What is a primary key? [1]

Answer 24

a field in a database that uniquely identifies a record

Question 25

Why do we use a primary key on a table? [2]

Answer 25

• to uniquely identify the data
• make sure there’s no repeats

Question 26

What is an example of the main primary key used? [1]

Answer 26

user ID

Question 27

What does a field that is a primary key contain? [1]

Answer 27

data values that are never repeated in the table

Question 28

What issues are faced on a table without a primary key? [2]

Answer 28

• update / modification issues
• insertion issues as rows wouldn’t be uniquely identified

Question 29

What are the advantages of using database system over flat file system? [3]

Answer 29

• imrpoved data security and consistency
• enhanced data access and sharing
• makes data management more efficient and structured

Question 30

What does SQL stand for? [1]

Answer 30

Structured Query Language

Question 31

Why is SQL used? [2]

Answer 31

• used to obtain information from single-table databases
• for writing scripts to obtain useful information from a database

Question 32

What are the possible miconceptions about SQL? [3]

Answer 32

• it’s case insensitive
• end every command with a semi colon
• must be used to separate items

Question 33

What are the shortcuts used for SQL scripts? For example how are the data types identified. [3]

Answer 33

• text: varchar
• length of data type: (__)
• number: int

Question 34

What is the script for creating a database? [1]

Answer 34

create database ___ ;

Question 35

What is the script for creating a table? [2]

Answer 35

create table __(table name)__
(fieldname#1 datatype,
fieldname#2 datatype,
fieldname#3 datatype) ;

Question 36

What is the script for inserting data into a table? [2]

Answer 36

insert into _(table name)__
(fieldname#1, fieldname#2, fieldname#3)
values (value#1, value#2, value#3) ;

Question 37

What is the script for selecting all the data from a table? [1]

Answer 37

select * from __(table name)__;

Question 38

What is the script for selecting a particular field of data from a table? [2]

Answer 38

select __(field name)__ from __(table name)__ ;

Question 39

What is the script for selecting multiple fields of data from a table? [2]

Answer 39

select __(field#1)__, __(field#2)__ from __(table name)__ ;

Question 40

What is the script for selecting all the data based on a condition? [2]

Answer 40

select * from __(table name)__
where __(condition)__ ;

Question 41

What is the script for selecting all the data based on multiple conditions? [2]

Answer 41

select * from __(table name)__
where __(condition#1)__ and __(condition#2)__ ;