A level Normalisation

What is the main purpose of normalising to 3NF in databases?

• To increase data redundancy

• To make databases more efficient by eliminating data redundancy

• To make databases more complex

• To store duplicate information for backup purposes

Answer explanation

The main purpose of using normal forms in databases is to make databases more efficient by eliminating data redundancy.

What does Third Normal Form (3NF) help to avoid in a database? (PICK 2)

• Unique information

• Redundant information

• Efficient data storage

• Organized data

• Inconsistent data

Answer explanation

Third Normal Form (3NF) helps to avoid duplicate address information in a database by ensuring that each piece of data is stored in only one place, reducing redundancy and improving data integrity.

How does 3NF improve the efficiency of a database?

• By storing the same information multiple times

• By making it easier to search and update information

• By linking each guest to their corresponding address with a name

• By creating a separate table for each entity

Answer explanation

3NF improves the efficiency of a database by making it easier to search or update information, reducing redundancy and ensuring data integrity.

How does 3NF work to reduce data redundancy?

• It allows storing the same data multiple times.

• It separates related information into different entities.

• It combines all data into a single table.

• It increases the number of primary keys

Answer explanation

Using 3NF separates repeating information into different tables, reducing data redundancy and improving data integrity.

Which normal form is primarily concerned with reducing redundancy and dependency by ensuring that each attribute is dependent on the primary key?

• First Normal Form (1NF)

• Second Normal Form (2NF)

• Third Normal Form (3NF)

• Boyce-Codd Normal Form (BCNF)

Answer explanation

Third Normal Form (3NF) is primarily concerned with reducing redundancy and dependency by ensuring each attribute is dependent on the primary key.

Normalisation is...

• Removing all necessary data from a database

• Organising a database to remove repeated entries and reduce the likelihood of inconsistent data

• Putting attributes from different entities into one big database

• Identifying the primary key for each entity

A relation is in 1NF if it doesn't contain any ____________?

• Determinants

• Repeating groups

• Null values in primary key fields

• Functional dependencies

A relation is in 2NF if it meets the requirements for 1NF and what other condition is met?

• There are no functional dependencies.

• There are no null values in primary key fields.

• There are no repeating groups.

• There are no attributes that are not functionally dependent on the relation's primary key.

What is a foreign key?

• A unique identifier in a database

• A primary key of one table that appears in another table

• A field that should not be in a table and needs removing

Which of the following statements fully describes data in 2NF:

• When any repeating fields have been removed and the table is given a primary key

• When all repeating entries of data are removed and the fields in each table are directly related to the primary key and no fields are present that are not related to each other

• When all the fields in each table are directly related to the primary key