For analytical purposes, data warehouses have evolved. Data warehouses support historical data. You should not confuse a data warehouse's historical data with temporal data, the subject of this chapter. In a data warehouse, historical data means just archived non-temporal data from the past; a typical data warehouse holds from 5 to 10 years of data for analytical purposes. Data warehouses are not suitable for business applications because a data warehouse typically has no constraints.
Data warehouses have a simplified data model that consists of multiple star schemas. You can see a typical star schema in the following figure:
Star schema
One schema covers one business area. It ...
