1. DSS & Warehousing Systems
Chapter 12
Efrem Mallach
Prepared by
Luvai Motiwalla
Irwin/McGraw-Hill
Copyright © 2000 by The McGraw-Hill Companies, Inc. All rights reserved.

2. Data Warehousing and Executive Information System Fundamentals
Introduction
Characteristics of a data warehouse
Who uses data warehouses?
Why data warehouses now?
Data warehouse concepts
Executive information systems

3. Introduction What is a data warehouse?
A data warehouse is a collection of a wide variety of corporate data. Organized and made available to end users for decision – making purposes
Pages 467 to 469
Data ware houses are used by managers and knowledge workers who require access to this data. For analyzing the business and planning its future. The warehouse system includes capabilities for retrieving items that are known to be there or for checking to see what items of potential value happen to be there.

4. Characteristics of a Data Warehouse
A data warehouse contains a lot of data.This data comes form outside and within the organization.
The data ware house is organized so as to facilitate the use of this data for decision making purposes.
The data warehouse provides tools by which end users can access this data.
Page 469

5. Who Uses Data Warehouses?- cont’d
Data warehouses are used by managers and knowledge workers who require access to this data for analyzing the business and planning its future.
Page 470
The data ware house provides flexibility to meet the usually unstructured and unpredictable needs. Knowing what these needs are, and how the data warehouse will meet them, is a critical first step in any data warehousing project.

6. Who Uses Data Warehouses?
Some people don’t need a data warehouse:
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Some people don’t need a data warehouse:
They are anyone whose job involves dealing with individual data records. Anyone whose job is to just up date the organizational database.Anyone with the technical skills to delve into complex SQL queries.
This means that data warehouses aren’t the universal solution to all of a business’s information needs.

7. Why Data Warehouses Now?- cont’d
The reason people started using data warehousing now are because previously it was unpractical as far as storage of data was concerned.
Page 471

8. Why Data Warehouses Now?
Once people became self sufficient in computing , they started asking direct access to the data they needed in their work.
Until the storage capacity and processing power to deal with it were available there was no motivation by the software companies to develop the access tools. Once people became self sufficient in computing , they started asking direct access to the data they needed in their work.

9. Data Warehouse Concepts- cont’d
Justifying the data warehouse
Pages 472 to 476
Justifying the data warehouse:
Before planning any data warehouse, it is important to to build the business case for the data warehouse project. The case must state what types of data will be included. And the way and kind of decision s that will be made with the data, and how decisions made with it will benefit the organization.

10. Data Warehouse Concepts
The data warehouse architecture:
An overall system architecture is important for a data warehouse. There are several elements of a data warehouse, and major external entities with which a data warehouse interacts.
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The major elements of a data warehouse, and the major external entities with which a data warehouse interacts, include:
The transactional or other operational databases from which the data warehouse is populated.
A process to extract data fro this database, or these databases, and bring it into the data warehouse.
A process to clean the data.
A process to load the cleansed data into the data warehouse database.
A process to create any desired summaries of the data.
Metadata, data about data.
The data warehouse database itself.
Query tools.
The user or users for whom the data warehouse exists and without whom it would be useless.

11. Executive Information Systems- cont’d
What is an executive information system?
It is an information system that provides information to top executives to support their decision – making needs.
Pages 476 to 484
Executives’ decision support needs differ from those of lower – level managers because executives decisions are typically less structured, less repetitive, more strategic, less detailed oriented, and more externally focused than those of other mangers.
An executive support system adds communication and analysis capabilities to the underlying executive information systems. EIS can operate in either of two modes: directly on line to their database or via prestored screens.

12. Executive Information Systems- cont’d
Reasons for using executive information systems include:
Solving specific problems in decision making or control in the organization, sending a signal to subordinates, and gaining computer literacy.
More and more systems are going beyond these original reasons and providing EIS –type support to many non executives, as the type of information contained in an EIS can be valuable to other decision makers as well.

13. Executive Information Systems
EIS developers must be conscious of:
(a) The need for a committed EIS sponsor, (b) the likely high cost of the EIS, (c) potential management resistance to the EIS,(d) potential employee resistance to the EIS.
To deal with these factors and implement a successful EIS, you should identify a sponsor, identify your sponsors motivation to use an EIS, define your expectations within your corporate culture, pick one or few initial topics that are important to you sponsor and do them well, define your data communication requirements, make sure enough resources are in place, pick packages to support your EIS, develop a prototype, and prepare to offer the necessary user training.