a presentation about brief introduction to the concept of data warehouse

1. data warehousing overviewGood decisions by effectively managing data Presented to : Eng. ShahinazAzab Presented by : Ahmed Gamal Mohammed SWE2 – ITInc . Intake 30 2009/2010

2. Outline Forethought What is Data Warehousing ? Architecture of Data Warehousing Data warehousing methodologies Advantages of using Data Warehousing Disadvantages of using Data Warehousing Conclusion 2

3. Forethought “Today every company is an information company but not all are prepared to deal with it.“ Mark Lahr – 3M Corp "The CEO will always get good data, but the challenge is making it available to the masses. That’s the challenge, how do you democratize decision-making?" Eric Berg, chief administrative officer and former CIO-Goodyear. 3

4. What is date warehouse ? “collection of data that is used primarily in organizational decision making.” -- W.H. Inmon, credited with initially using the term Data Warehouse, 1992 4

5. Also means ` A data warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process. It is :- Subject-Oriented. Integrated. Time-Variant. Non-volatile. 5

6. Architecture of Data Warehousing Operational database layer The source data for the data warehouse Data access layer The interface between the operational and informational access layer Metadata layer The data directory - This is usually more detailed than an operational system data directory. Informational access layer The data accessed for reporting and analyzing and the tools for reporting and analyzing data 6

7. Typical DW Architecture Data Store Data Access Data Sources ETL Presentation Dashboards The Data Warehouse System A Prompted Views System B Scorecards System C Extract Transform Load Business Model Ad-Hoc Reporting System D Self Serve 7

8. Data warehousing methodologies Bottom-up design Ralph Kimball, a well-known author on data warehousing, is a proponent of an approach to data warehouse design In this approach data marts are first created to provide reporting and analytical capabilities for specific business processes. Top-down design Bill Inmon, is one of the leading proponents of the top-down approach to data warehouse design. In this approach data warehouse is designed using a normalized enterprise data model. "Atomic" data, that is, data at the lowest level of detail, are stored in the data warehouse. 8

9. Advantagesof using Data warehousing Prior to loading data into the data warehouse, inconsistencies are identified and resolved. This greatly simplifies reporting and analysis. Because they are separate from operational systems, data warehouses provide retrieval of data without slowing down operational systems. 9

10. Disadvantages of using data warehousing Data warehouses are not the optimal environment for unstructured data. Because data must be extracted, transformed and loaded into the warehouse, there is an element of latency in data warehouse data. 10

11. Conclusion 11 Implementing a Data Warehouse is not a project, but a long term commitment to implement continuously improving business intelligence practices…

12. 12 Thank you for your listening At the end