lecture 1-b

Data WarehousesLecture 1

Evolution of Decision Support Systems

Overview

Most organizations began information processing on a small scale, automating one application at a time.

Systems tended to grow independently to support defined functional areas.

Each functional area tended to plan and develop systems in isolation from other areas.

Evolution of Information Processing

File Transaction Processing Data Based Management Systems (DBMS) 4GLs & MIS Extract Processing Decision Support Systems (DSS)

File Transaction Processing

The traditional approach to file processing encouraged each functional area to develop and maintain specialized applications.

Individual applications ran on unique master files.

Problems With Traditional File Processing:

Data redundancy Lack of data integrity Program-data dependency Lack of flexibility Poor security Lack of data sharing and availability

Traditional File Processing

Data redundancy and inconsistency across files:

File AStudent ID

NameAddressZIP Code

Phone Number

Registration Application

Library Application

Financial aidsApplication

Credit RecordsApplication

File BStudent IDFirst NameLast Name

Address & ZIPPhone Number

File CStudent ID

First & Last NameAddressZIP Code

Phone Number

File DSocial Security

NameAddressZIP Code

Phone Number


File Transaction Processing Data Based Management Systems (DBMS) 4GLs & MIS Extract Processing Decision Support Systems (DSS) Data Warehouses OLAP Data Mining

Data Base Management Systema single source for all processing

Registration IS application

Library IS application

Financialaids application

Credit RecordsIS application

DBMS- database management system

INTEGRATED STUDENTS DATABASE

Students:Name

Address

Credit Records:Number of creditsCourse number

Books:Title

Author

Data DefinitionLanguage

Data ManipulationLanguage

CommonData Dictionary



4GLs, MIS

Fourth-Generation Languages brought access to data and users at the level of the end-user.

MIS – focus on providing information to support management decisions



Extract Programs An attempt by IT to anticipate somehow the

types of reports that would be requested from time to time.

IT would create and keep the extract files to fulfill any requests for special reports. For any reports that could not be run off the extracted files, IT would write individual special programs.



Decision Support Systems More sophisticated systems intended to

provide strategic information. These systems were supported by extracted files.

The systems were menu-driven and provided online information.

Many of such decision-support systems were for marketing.

FAILURES OF PAST DECISION-SUPPORT SYSTEMS

IT receives too many ad hoc requests, resulting in a large overload. With limited resources.

IT is unable to respond to the numerous requests in a timely fashion; Moreover, the users need more reports to expand and understand the earlier reports.

The users have to depend on IT to provide the information. They are not able to access the information themselves interactively.

The information environment ideally suited for making strategic decision making has to be very flexible and conducive for analysis.

factors relating to the inability to provide strategic information

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OPERATIONAL VERSUS DECISION-SUPPORT SYSTEMS

Operational systems are online transaction processing (OLTP) systems. These are the systems that are used to run the day-to-day core business of the company. They are the so-called bread-and-butter systems.

These systems typically get the data into the database. Each transaction processes information about a single entity such as a single order, a single invoice, or a single customer.

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On the other hand, specially designed and built decision-support systems are not meant to run the core business processes. They are used to watch how the business runs, and then make strategic decisions to improve the business.

as opposed to OLTP systems that are designed to put the data into the database. Decision- support systems are developed to provide strategic information.

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Operational and informational systems.

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Motivation

We need to design and build informational systems That serve different purposes Whose scopes are different Whose data content is different Where the data usage patterns are different Where the data access types are different



Documents

lecture 1-b