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Database Terminology
1. A database is
A collection of data or information which is held together in an organised or logical way
2. An example of a paper-based database is
Address book
Birthday book
Yellow pages
Any other sensible answer
3. Three examples of computerised databases are
Search engines e.g. Google
Electronic school registers
Library database of books and loans
Police criminal database
Any other sensible answer
4. Computerised Vs paper-based databases:
Computerised database
Can hold a vast amount of data
Very fast to search for a record
Can be easily amended or updated
Records are stored safely
Data can be easily sorted on multiple
criteria
Can easily analyse data e.g. most popular
item sold
Easy to make a backup
Paper-based database
Can only hold what can be stored in a
limited physical space
Can take a long time to manually search
through records
Changes have to be done manually – can
look untidy
Records can be lost or misfiled
Not easy to sort on more than one criteria
Difficult to analyse data
Making up-to-date backups is time
consuming
5. Explain why a database is suitable for storing information
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Vast amounts of information can be stored
Queries can be run to search for a specific records or group of records
Reports can be produced from the data stored or queries
Information can be extracted and exported into a word processing package for
mail merging
Validation can be used to reduce errors
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6. A database table stores
Information in the form of records
7. A record is
All of the data or information about one person or one thing
8. An example of a record might look like
Title
Mrs
Forename
Sally
Surname
Chadwick
Date of Birth
14/05/62
9. A record is made up of fields. A field is
One piece of data or information about a person or thing
10. Two examples of fields might be
First name
Eye colour
Height
Any sensible answer
11. Explain what is meant by a ‘flat-file database’
A database which contains only one table.
12. Explain what is meant by the term ‘data duplication’
Where data is unnecessarily repeated
13. List the problems that may occur as a result of using a flat-file database
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Data duplication can result in a much larger database than necessary
More hard disk space is needed to store the database
Data duplication makes the database slower to search
High risk of data entry errors as the same data has to be entered repeatedly
14. Explain how a relational database can overcome the problems of a flat-file
database.
To overcome the problems with flat file databases and reduce data duplication,
relational databases are used.
Data is split up into sensible groups and a separate table is made for each group.
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15. Define the term, ‘primary key’
The primary key is a field in a table which allows each record to be uniquely identified.
16. Give two examples of a primary key
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Customer ID
Product ID
Driving licence number
Bank account number
Hospital patient number
Any sensible answer
17. List three things which are important about a primary key
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Each record must have a primary key
The primary key must be unique to that record
You should be able to identify any record by its primary key.
18. Explain what is meant by a ‘simple primary key’ and give an example
A simple primary key is made up of a single field only e.g. customer number
19. Explain what is meant by a compound or composite primary key and give an
example
A compound / composite primary key combines more than one field to make a unique
value. e.g. each card in a deck would be identified by its suit and its value – Ace of
Hearts
20. Define the term, ‘secondary key’
A secondary key is made on a field that you would like to be indexed for faster
searches.
A table can have more than one secondary key.
21. Define the term, ‘foreign key’
A foreign key is used to link tables together and create a relationship.
It is a field in one table that is linked to the primary key in another table
22. Explain what is meant by ‘referential integrity’
Every foreign key value has a matching value in the corresponding primary key.
Referential integrity uses these to ensure that there are no orphan records i.e. it
prevents you from deleting related records.
Foreign key – customer ID in rentals table, primary key – customer ID in customer
table
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