The Information CrisisYou may be working in the Information Technology Department of a large conglomerateor you may be part of a medium-sized company. Whatever the size of your company mayESCALATING NEED FOR STRATEGIC INFORMATION 3INTEGRATEDMust have a single, enterprise-wide view.DATA INTEGRITYInformation must be accurate and mustACCESSIBLE conform to business rules.Easily accessible with intuitive accesspaths, and responsive for analysis.

CREDIBLEEvery business factor must have one andonly one value.Information must be available within thestipulated time frame.

We are faced with two startling facts: (1) organizations have lots of data; (2) informationtechnology resources and systems are not effective at turning all that data into useful strategic information.

Digital storage is costing lessand less, and network bandwidth is increasing as its price decreases. Specifically, we haveseen explosive changes in these critical areas:_ Computing technology_ Human/machine interface_ Processing options

A New Type of System EnvironmentThe desired features of the new type of system environment are:_ Database designed for analytical tasks_ Data from multiple applications_ Easy to use and conducive to long interactive sessions by users_ Read-intensive data usage_ Direct interaction with the system by the users without IT assistance_ Content updated periodically and stable_ Content to include current and historical data_ Ability for users to run queries and get results online_ Ability for users to initiate reportsProcessing Requirements in the New EnvironmentMost of the processing in the new environment for strategic information will have to beanalytical. There are four levels of analytical processing requirements:1. Running of simple queries and reports against current and historical data2. Ability to perform “what if ” analysis is many different ways

3. Ability to query, step back, analyze, and then continue the process to any desiredlength4. Spot historical trends and apply them for future results

DATA WAREHOUSE DEFINED_ Provides an integrated and total view of the enterprise_ Makes the enterprise’s current and historical information easily available for decisionmaking_ Makes decision-support transactions possible without hindering operational systems_ Renders the organization’s information consistent_ Presents a flexible and interactive source of strategic informationA Simple Concept for Information DeliveryAn Environment, Not a Product_ An ideal environment for data analysis and decision support_ Fluid, flexible, and interactive_ 100 percent user-driven_ Very responsive and conducive to the ask–answer–ask–again pattern_ Provides the ability to discover answers to complex, unpredictable questionsA Blend of Many Technologies

Let us reexamine the basic concept of data warehousing. The basic concept of data warehousing

is:_ Take all the data from the operational systems_ Where necessary, include relevant data from outside, such as industry benchmarkindicators_ Integrate all the data from the various sources_ Remove inconsistencies and transform the data_ Store the data in formats suitable for easy access for decision makingAlthough a simple concept, it involves different functions: data extraction, the functionof loading the data, transforming the data, storing the data, and providing user interfaces.

DEFINING FEATURES of data wareouse1 Subject-Oriented Data:in the operational is

system data is sotered by apllicatios but in data warehouse data is stored by subjects

Example: In the operational systems shown, data for each application is organizedseparately by application: order processing, consumer loans, customer billing, accountsreceivable, claims processing, and savings accounts. For example, Claims is a criticalbusiness subject for an insurance company. Claims under automobile insurance policies are processed in the Auto Insurance application.Similarly, claims data for workers’ compensation insuranceis organized in the Workers’ Comp Insurance application But in the data warehouse for an

insurance company, claims data are organized around the subject of claims and not by individualapplications of Auto Insurance and Workers’ CompOperational ApplicationsOrderProcessing2 ConsumerLoans3 CustomerBilling4 AccountsReceivableClaimsProcessingSavingsAccountsData Warehouse SubjectsSales ProductClaims PolicyAccountCustomer

Integrated DataThe data in the data warehouse comes from several operational systems.Source data are in different databases, files, and data segments. These are disparate applications,so the operational platforms and operating systems could be different. The filelayouts, character code representations, and field naming conventions all could be different.In addition to data from internal operational systems, for many enterprises, data fromoutside sources is likely to be very important.Data inconsistencies are removed; data from diverse operationalapplications is integrated.DATA FROM APPLICATIONS

SavingsAccountLoansAccountCheckingAccountDATA WAREHOUSE SUBJECTSSubject= AccountThe time-variant nature of the data in a data warehouse_ Allows for analysis of the past_ Relates information to the present_ Enables forecasts for the futureNonvolatile DataData extracted from the various operational systems and pertinent data obtained fromoutside sources are transformed, integrated, and stored in the data warehouse. The datain the data warehouse is not intended to run the day-to-day businessData GranularityData granularity refers to the level of detail. Depending on therequirements, multiple levels of detail may be present. Many datawarehouses have at least dual levels of granularity.

In an operational system, data is usually kept at the lowest level of detailDATA WAREHOUSES AND DATA MARTS