Monday, 3 March 2014

LOGICAL AND PHYSICAL DESIGN OF DATA WAREHOUSE

Logical design:

Logical design deals with the logical relationships between objects. Entity-relationship (ER) modeling technique can be used for logical design of data warehouse. ER modeling involves identifying the entities (important objects), attributes (properties about objects) and the relationship among them.

An entity is a chunk of information, which maps to a table in database. An attribute is a part of an entity, which maps to a column in database.

A unique identifier can be used to make sure the data is consistent.

Physical design:

Physical design deals with the effective way of storing and retrieving the data. In the physical design, the logical design needs to be converted into a description of the physical database structures.

Physical design involves creation of the database objects like tables, columns, indexes, primary keys, foreign keys, views, sequences etc. 

DBT - Models

Models are where your developers spend most of their time within a dbt environment. Models are primarily written as a select statement and ...