Characteristics of Data Warehousing The data warehouse is that portion of an overall Architected Data Environment that serves as the single integrat integrated ed source source of data for processi processing ng informat information. ion. The data warehouse warehouse has specific characteristics that include the following: 1) Subj Subjec ectt-Or Orie ient nted ed:: Information is presented according to specific subjects or areas of interest, not simply as computer files. Data is manipulated to provide information about a particular subject. or e!ample, the "#D$ is not simply made accessible to end%users, but is provided structure and organi&ed according to the specific needs. 2) Inte Integr grat ated ed:: A single source of information for and about understanding multiple areas of interest. The data warehouse provides one%stop shopping and contains information about a variety of subjects. Thus the 'I#A( data warehouse has information on students, faculty and staff, instructional wor)load, and student outcomes. 3) NonNon-Vo Voa ati tie e:: "table "table informat information ion that doesn*t doesn*t change change each each time an operati operationa onall process process is e!ecute e!ecuted. d. Information is consistent regardless of when the warehouse is accessed. !) "i#e "i#e-V -Var aria iant nt:: +ontaining a history of the subject, as well as current information. istorical information is an important component of a data warehouse. $) %cce %ccess ssib ibe e:: The primary purpose of a data warehouse is to provide readily accessible information to end%users. &) 'roc 'roces esss-Or Orie ient nted ed:: It is important to view data warehousing as a process for delivery of information. The maintenance of a data warehouse is ongoing and iterative in nature.
(enefits of Data Warehousing The successful implementation of a data warehouse can bring major, benefits to an organi&ation including: 1) 'otentia igh *eturns on In+est#ent: Implementation of data warehousing by an organi&ation re-uires a huge investment typically from #s / lac) to 0/ lac)s. owever, a study by the International Data +orporation 1ID+2 in 334 reported that average three%year returns on investment 1#' I2 in data warehousing reached 5/6. 2) Co#,etiti+e %d+antage: The huge returns on investment for those companies that have successfully implemented a data warehouse is evidence of the enormous competitive advantage that accompanies this technology. The competitive advantage is gained by allowing decision%ma)ers access to data that can reveal previously unavailable, un)nown, and untapped information on, for e!ample, customers, trends, and demands. 3) Increased 'roducti+it of Cor,orate Decision-.a/ers: Data warehousing improves the productivity of corporate decision%ma)ers by creating an integrated database of consistent, subject%oriented, historical data. It integrates data from multiple incompatible systems into a form that provides one consistent view of the organi&ation. $y transforming data into meaningful information, a data warehouse allows business managers to perform more substantive, accurate, and consistent analysis. !) .ore cost-0ffecti+e Decision-.a/ing: Data warehousing helps to reduce the overall cost of the7 product7 by reducing the number of channels. $) (etter enter,rise inteigence It helps to provide better enterprise intelligence. 8 Enhanced customer service. 8 It is used to enhance customer9 service.
&) Dei+ers and 0nhanced (usiness Inteigence: $y providing data from various sources, managers and e!ecutives will no longer need to ma)e business decisions based on limited data or their gut. In addition, data warehouses and related $I can be applied directly to business processes including mar)eting segmentation, inventory management, financial management, and sales.; ) Sa+es "i#e:
"ince business users can -uic)ly access critical data from a number of sources
A data warehouse implementation includes the conversion of data from numerous source systems into a common format. "ince each data from the various departments is standardi&ed, each department will produce results that are in line with all the other departments. "o you can have more confidence in the accuracy of your data. And accurate data is the basis for strong business decisions. 5) 'ro+ides istorica Inteigence
A data warehouse stores large amounts of historical data so you can analy&e different time periods and trends in order to ma)e future predictions. "uch data typically cannot be stored in a transactional database or used to generate reports from a transactional system.
'robe#s of Data Warehousing The problems associated with developing and managing a data warehousing are as follows: 1) 6nderesti#ation of *esources of Data 7oading: "ometimes we underestimate the time re-uired to e!tract, clean, and load the data into the warehouse. It may ta)e the significant proportion of the total development time, although some tools are there which are used to reduce the time and effort spent on this process.
2) idden 'robe#s 8ith Source Sste#s: "ometimes hidden .problems associated with the source systems feeding the data warehouse may be identified after years of being undetected. or e!ample, when entering the details of a new property, certain fields may allow nulls which may result in staff entering incomplete property data, even when available and applicable. 3) *e9uired Data not Ca,tured: In some cases the re-uired data is not captured by the source systems which may be very important for the data warehouse purpose. or e!ample the date of registration for the property may be not used in source system but it may be very important analysis purpose. !) Increased 0nd-6ser De#ands: After satisfying some of end%users -ueries, re-uests for support from staff may increase rather than decrease. This is caused by an increasing awareness of the users on the capabilities and value of the data warehouse. Another reason for increasing demands is that once a data warehouse is online, it is often the case that the number of users and -ueries increase together with re-uests for answers to more and more comple! -ueries. $) Data o#ogeniation The concept of data warehouse deals with similarity of data formats between different data sources. Thus, results in to lose of some important value of the data. &) igh De#and for *esources The data warehouse re-uires large amounts of data. ) Data O8nershi, Data warehousing may change the attitude of end%users to the ownership of data. "ensitive data that owned by one department has to be loaded in data warehouse for decision ma)ing purpose. $ut some time it results in to reluctance of that department because it may hesitate to share it with others. ) igh .aintenance Data warehouses are high maintenance systems. Any reorgani&ation7 of the business processes and the source systems may affect the data warehouse and it results high maintenance cost. 5) 7ong-Duration 'rojects
The building of a warehouse can ta)e up to three years, which is why some organi&ations are reluctant in investigating in to data warehouse. "ome only the historical data of a particular department is captured in the data warehouse resulting data marts. Data marts support only the re-uirements of a particular department and limited the functionality to that department or area only. 1;) Co#,e
