A Manager might have to spend a lot of time locating and gathering the needed data for decision making, or s/he may be forced to make decision based on incomplete knowledge.
Also, Manager might face with troubles if s/he wants to find data about past events since most firms only make the current data immediately available. - Data Warehousing address all of these problems.
The data originated in many Core Operational Transaction Systems, such as
Sales, Customer Accounts and Manufacturing, as well as data from
Web site transactions and from outside databases are consolidates and
standardize in a Data Warehouse.
As a result of Data Warehouse, information from different Operational Databases can be used across the Enterprise Management for Analysis and Decision making.