Normalization

Normalisation is:

• Removing all necessary data from a database

• Organising a database to remove repeated entries and increase the accuracy of the data

• Putting fields from different tables into one big database

An advantage of normalisation is:

• The storage space needed for a normalised database is likely to be smaller

• The process of normalising a database is very easy and doesn’t require any skill

• It is possible to see previous details that have been changed, such as a customer’s address, as we can look back at an older entry

An entity is represented by what in a database?

• Table

• Row

• Column

• Cell

An attribute is represented by what in a database?

• Table

• Row

• Column

• Cell

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

What is a functional dependency?

• when an non-key attribute is determined by a whole part of a COMPOSITE primary key.

• When a key field is changed and it conflicts with another key

• When a database function is dependant of the operation of another function to work correctly

• When data is a database is repeated for different entities

What is a composite primary key?

• A primary key that can be duplicated in the same table

• An attribute that is a primary key in another table

• A foreign key that is a primary key in more than one other table

• A primary key made up from two or more attributes

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

• Determinants

• Repeating columns

• Null values in primary key fields

• Functional dependencies

After being in 1NF, a table is in 2NF if it has...

• only one primary key field

• all of its fields are Whole Key Dependant

• non-key fields that are functionally dependant

• at least one repeating group

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