Database Normalisation Retrieval Quiz (Yr14)

Which of the following best defines referential integrity in the context of databases?

• A foreign key must correspond to a valid/existing primary key in another table.

• All data must be stored in a single table.

• Every table must have only one column.

• Data must be encrypted at all times.

What is the main aim of normalisation in databases?

• To allow for all possible relationships between data and minimise duplication, preventing inconsistencies.

• To increase the number of tables in a database.

• To store all data in a single table.

• To make data retrieval slower.

Which statement best describes a normalised entity?

• An entity that contains no redundant data.

• An entity that contains only numeric data.

• An entity that is not related to any other entity.

• An entity that is always a primary key.

According to the rules of third normal form (3NF), what must all non-key attributes be dependent on?

• The key, the whole key, and nothing but the key.

• Any attribute in the table.

• Only the foreign key.

• The first attribute in the table.

A table is in second normal form (2NF) if:

• It is in first normal form and all non-key dependencies are fully dependent on the primary key.

• It contains only one row.

• It has no primary key.

• It is not related to any other table.

What is the solution when partial key dependencies exist in a table that is being normalised to 2NF?

• Remove these fields into a new table with a copy of the dependent part primary key.

• Delete all non-key attributes.

• Merge all tables into one.

• Remove the primary key from the table.

Which of the following is a requirement for a table to be in Third Normal Form (3NF)?

• The table must have only one attribute.

• There are no partial key dependencies and no non-key dependencies.

• The table must have only numeric data.

• The table must have duplicate rows.

What is the main solution to avoid non-key attributes depending on another non-key attribute in a database table?

• Delete all non-key attributes.

• Move the attributes that depend on another non-key attribute to another table, with a copy of the attribute they depend on.

• Combine all attributes into a single column.

• Ignore the dependencies.

Why is it important for a table in 3NF to have no transitive dependencies?

• To ensure that all data is stored in a single table.

• To prevent non-key attributes from depending on other non-key attributes, which improves data integrity.

• To allow for more duplicate data.

• To make the table easier to read.

Which of the following statements best describes a table in First Normal Form (1NF)?

• All attributes are atomic and there are no repeating groups of attributes.

• All attributes are composite and there are repeating groups of attributes.

• All attributes are dependent on a non-key attribute.

• All attributes are foreign keys.