Normalisation

What is normalisation?

• The process used to optimize database performance
• The process used to come up with the best possible database design
• The process of adding redundancy to data for faster retrieval
• The process of converting database tables into text files for storage

Which of the following is a characteristic of First Normal Form (1NF)?

• Data is duplicated within the same table or across multiple tables
• Each table contains repeating attributes or groups of attributes
• A single attribute cannot be made up of more than 1 data item
• The table contains partial dependencies

What does First Normal Form (1NF) ensure, above all else?

• All attributes are dependent on the primary key
• All attributes contain partial dependencies

• The table contains no repeating attributes or groups of attributes
• The table has no transitive dependencies

Which condition must be met for a table to be in Second Normal Form (2NF), assuming it already meets First Normal Form (1NF)?

• Every attribute in the table is dependent on the primary key
• The table contains no repeating attributes or groups of attributes
• Each attribute is atomic and cannot be broken down further
• The table has no transitive dependencies

What is the purpose of Second Normal Form (2NF)?

• Ensures that each table has a single purpose
• Ensures that data is not duplicated within the same table or across multiple tables
• Ensures that each attribute is atomic and cannot be broken down further
• Ensures that no attribute in the table has a transitive dependency

What is Third Normal Form (3NF)?

• Ensures that each table has a single purpose
• Ensures that data is not duplicated within the same table or across multiple tables
• Ensures that every attribute in the table is dependent on the primary key
• Ensures that every attribute is also not dependent on any other attribute, eliminating transitive dependencies

What is a transitive dependency?

• When every attribute in a table is dependent on the primary key
• When an attribute is dependent on another attribute

• When the table contains repeating attributes or groups of attributes
• When the table is not normalized

Select all benefits of normalisation

• Only one table needs to be changed
• It makes complex queries (searches) easier to perform
• Data integrity is maintained
• It makes it difficult to sort the table using certain attributes

What does meeting Third Normal Form (3NF) ensure, assuming it already meets First and Second Normal Form (2NF)?

• All attributes are dependent on the primary key
• Each attribute is atomic and cannot be broken down further
• The table has no transitive dependencies
• Every attribute is also not dependent on any other attribute, eliminating transitive dependencies

Identify all characteristics of Second Normal Form (2NF)

• Every attribute in the table is dependent on the primary key
• Each table contains repeating attributes or groups of attributes
• A single attribute cannot be made up of more than 1 data item
• The table contains partial dependencies