Chapter 2

Applications of Data Warehousing

Review Questions

1. How are OLAP and OLTP different?

OLAP	OLTP
Designed for read-only analysis of historical data	Designed for real-time inserting, updating, and deleting of current data
Stores the data in dimensions	Stores data in relational tables
Built to be queried	Built for transaction processing
Denormalized format	Normalized format
Heavily indexed	Limited indexing

2. True or false: An OLAP system is the best place to query the status of a particular order (explain your answer).

False. OLAP systems often contain summaries of orders, but they seldom contain individual orders. The best place to query order status is the OLTP system that originated the order.

3. In the following table, evaluate which attributes are characteristic of each different type of data.

Attribute	OLAP	OLTP
Consolidated	X
Consistent	X	X
Read-write		X
Subject oriented	X
Historical	X
Read-only	X
Detailed		X
Granular	X

4. What are the disadvantages of using an OLTP system to conduct analytical processing?

It is difficult to design analytical reports, indexes reduce performance, and it is a complex data model.