Databases - Design - 1

Question 1

How many entities does one table hold the attributes for?

Answer 1

1

Question 2

When does one to many cardinality exist?

Answer 2

When one entity can be present in many different instances of another entity.

Question 3

What is a Data Dictionary and what do they contain?

Answer 3

They are used to plan information and includes the name and description of the attributes (fields) in each entity(table) within a database.

Question 4

Describe attributes AND entities, refering them to eachother

Answer 4

• An entity is a place where information about a concept is collected – a table. They are made up of attributes.
• Attributes describe the details of an entity (field)

Question 5

What are validation checks used for?

Answer 5

They ensure data is allowable, making it harder to make mistakes.

Question 6

Name and describe the 4 types of validation checks

Answer 6

• Range – ensures data is between a lower and upper limit
• Restricted Choice – limits the user to a list of options.
• Length Check – restricts number of characters that can be entered.
• Presence Check – ensures that the field is not left blank

Question 7

List the 6 laws in the GDPR act

Answer 7

• processed lawfully, fairly and in a transparent manner in relation to individuals
• used for the declared purpose only
• limited to the data needed for the declared purpose
• accurate
• not kept for longer than necessary
• held securely

Question 8

What is a relational database?

Answer 8

A database that is usually arranged across many tables, which can be joined via a primary or foreign key.