Data Types

Question 1

Identify different data types

Answer 1

• logical/Boolean
• alphanumeric/text
• numeric (real: 3.142, interger: whole number
• date
• currency (2dp)

Question 2

Describe what is meant by the terms file, record, field and key field

Answer 2

• field: one piece of data (e.g. name)
• record: information about one person or one thing
• key field: used to uniquely identify each individual record.

Question 3

Describe different database structures such as flat files and relational tables including the use of relationships, primary keys and foreign keys

Answer 3

• A flat-file database is one that only contains a single table of data.
• A relational database is one that contains two or more tables of data, connected by links called relationships.
• Note that to create the relationship, we are using the key field from one table to link it to another.
• When a key field from one table appears in a different table, we call this a foreign key.
• Flat file causes a lot of data duplication.
• Relational can be split up into sensible group which can be linked together

Question 4

State the difference between analogue data and digital data

Answer 4

• Analogue signal is one which has a value that varies smoothly
• Digital is in binary

Question 5

Explain the need for conversion between analogue and digital data

Answer 5

ADC converter

DAC converter