Datawarehouse is the storehouse or central repository for structured data. Data coming from various resources CRM, ERP, Billing, Supply chain, etc…., are first cleaned, transform, and then loaded into a storehouse called a data warehouse.

In order to store data in the data warehouse, we use a design pattern called Star Schema. Design patterns consist of facts & dimensions tables that resemble star.

Facts:

1) Facts are the numerical values, observations, and subject of analysis.

Example: temp, sales orders, exchange rates

Dimensions:

1) Dimensions are the textual values, and the context of analysis contains most attributes.

Example: product, people, places & concepts

Measures:

1) Measures are the property on which min, max, avg, count, sum, etc… calculations can be made.

In a star schema, facts and dimensions tables are linked with the help of primary and foreign keys of the tables.