Discuss the concepts associated with dimensionality modeling.

Question

What will be an ideal response?

Answer 1

Every dimensional model (DM) is composed of one table with a composite primary key,
called the fact table, and a set of smaller tables, called dimension tables. Each dimension table
has a simple (noncomposite) primary key that corresponds exactly to one of the components
of the composite key in the fact table. In other words, the primary key of the fact table is made
up of two or more foreign keys. This characteristic “star-like” structure is called a star schema
or star join. Another important feature of a DM is that all natural keys are replaced with
surrogate keys. This means that every join between fact and dimension tables is based on
surrogate keys, not natural keys. Each surrogate key should have a generalized structure based
on simple integers. The use of surrogate keys allows the data in the warehouse to have some
independence from the data used and produced by the OLTP systems.