H446 Database Normalisation

What is the main purpose of database normalisation?

• To make databases larger

• To reduce redundancy and improve consistency

• To increase the number of fields in a table

• To remove all primary keys

Which statement best describes First Normal Form (1NF)?

• Every non-key attribute depends on the whole key

• No non-key attribute depends on another non-key attribute

• Each field contains atomic values only

• Every table must have two primary keys

Which of the following breaks 1NF?

• A field called `Postcode` containing one postcode

• A field called `Subjects` containing `Maths, English, Biology`

• A field called `DOB` containing `12/06/2007`

• A field called `Age` containing `17`

In database normalisation, what does atomic mean?

• A field contains very important data

• A field contains one indivisible value

• A field contains only numbers

• A field must be a primary key

Which of the following is the best example of a composite key?

• StudentID

• Surname

• StudentID and CourseID together

• CourseName

A partial dependency can only occur when:

• There is no primary key

• The primary key is composite

• The table is already in 3NF

• A foreign key is present

Which statement best defines a partial dependency?

• A non-key attribute depends on part of a composite key

• A key depends on a non-key attribute

• A field contains more than one value

• Two tables are linked by a foreign key

A table has primary key `(StudentID, CourseID)` and also contains `StudentName`. What kind of dependency is this if `StudentName` depends only on `StudentID`?

• Functional dependency

• Transitive dependency

• Partial dependency

• Referential dependency

Removing partial dependencies moves a table from:

• UNF to 1NF

• 1NF to 2NF

• 2NF to 3NF

• 3NF to BCNF

Which of the following is most likely to be a transitive dependency?

• `StudentID → StudentName`

• `CourseID → CourseName` when CourseID is the full primary key

• `RecordID → TeacherInitials → TeacherName`

• `(StudentID, CourseID) → Grade`