Unit 5 - Databases

Question 0

Put Records, Table, Field and Characters in the correct order of what each is made up of?

Answer 0

A Table is made up from Records
Records are made up of Fields
Fields are made up of Characters

Question 1

Name the 6 key aspects to a database?

Answer 1

Field names
Fields
Table
Records
Data items
Primary key

Question 2

What is a table?

Answer 2

A structure of rows and columns that contain data

Question 3

What’s is a record?

Answer 3

A single row of the table holding data of a single item or event

Question 4

What is a field?

Answer 4

An individual data item within a record

Question 5

What is a primary key?

Answer 5

It’s a field in a table that allows each record to be uniquely identified

Question 6

What are the two types of primary key?

Answer 6

Simple

Compound/Composite

Question 7

What the difference between a simple and a compound primary key?

Answer 7

A simple primary key is one which is made up of a single field
A compound primary key is one that combines the content of mor than one field to produce a unique value

Question 8

What is a secondary key?

Answer 8

Field that is identified as being suitable for indexing data

Question 9

What is a foreign key?

Answer 9

It a key that allows tables to link together. The foreign key links to a primary key of another table

Question 10

What is an entity?

Answer 10

A thing that can be distinctly identified

Question 11

What are the three types of relationships?

Answer 11

One to one
One to many
Many to many

Question 12

Which relationship should not be in a normalised database?

Answer 12

Many to many

Question 13

Why is data normalised?

Answer 13

To reduce redundancy and inconsistency and easier to maintain

Question 14

2 characteristics of 1NF?

Answer 14

Every data value in a field is atomic

No repeating values

Question 15

Name the 4 checks for 1NF?

Answer 15

Is there a primary key?
Are the field names unique?
Are the repeating fields?
Is the data in the fields atomic?

Question 16

What are the rules of 2NF?

Answer 16

Must have been in 1NF

All non-key fields be found out by using the entire primary key?

Question 17

What happens in 3NF?

Answer 17

Table is split into multiple tables with only the fields that contain data on a topic

Question 18

What are the 5 advantages of normalisation?

Answer 18

Removes redundancy
Increases consistency 
Increases integrity
Easier to maintain
Flexibility for future changes

Question 19

What are the 3 disadvantages of normalisation?

Answer 19

Queries take longer and more usage
Structure makes it harder for reports
Historical data cannot be stored

Question 20

10 things from the data dictionary?

Answer 20

Table name
Field name
Field data type
Field length
Field value
Field validation
Table security
Keys
Indexes
Relationships

Question 21

What are the two types of queries?

Answer 21

Simple

Complex

Question 22

When should you use a simple query?

Answer 22

When 1 parameter needs to be searched for

Question 23

Name the three way to join parameter used in complex queries?

Answer 23

And
Or
Not