4.10 fundamentals of databases

What are the two types of relationships between tables in a database?

One-to-many and many-to-many

What is an entity?

An entity is an object about which data will be stored.

What is an attribute?

An attribute is a piece of information about an entity, which is implemented as a field in a relational database.

What is a primary key?

A primary key is an attribute in a table that uniquely identifies each record.

What is a foreign key?

A foreign key is an attribute that appears in more than one table and is used to create the link between tables. The foreign key in a table must be a primary key from another table.

What is normalisation?

Normalisation is the process of ensuring that a relational database conforms to certain rules that ensure that the data within it is stored in the most efficient way.

What is first normal form?

First normal form is when a table does not contain repeating attributes or repeating groups and all of the data in the table is atomic.

What is second normal form?

Second normal form is when the database is in first normal form and the attributes that depend on part but not all of the primary key are removed by creating additional tables.

What is third normal form?

Third normal form is when the database is in second normal form and all the non-key attributes that depend on other non-key attributes are removed by creating additional tables.