Metadata in data warehouse


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metadata in datawarehouse

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Metadata in data warehouse

  1. 1. Role of Metadata
  2. 2. Why Metadata  Before touches the keyboard by the prominent(superlative) users.  Several questions come to their mind. What are various data in the data warehouse? Is there information about unit sale and costs by product? How old is the data in the warehouse. When was the last time fresh data was brought in? Are there any summaries by month and product?
  3. 3. Why Meta data contd.,  These questions and several more information are very valid and pertinent.  What are answers? Where are the answers? Can ur user see the answers? How easy to get the answers?
  4. 4. What is Meta data?  Metadata in a data warehouse contains the answer to questions about the data in the data warehouse.  Keep the answer in a place called the metadata repository.
  5. 5. Different definitions for metadata  Data about the data.  Table of contents for the data.  Catalog for the data.  Data warehouse roadmap.  Data warehouse directory.  Tongs to handle the data.  The nerve center.
  6. 6. So, what exactly is metadata  It tells u more.  It gives more than the explanation of the semantics and the syntax.  Describes all the pertinent(relevant) aspect of the data in the data warehouse.  Pertinent to whom?  The answer is – primarily to the user and also developer and even project team.
  7. 7. Meta data
  8. 8. Why it is important?  Metadata is necessary for using, building and administering your data warehouse.
  9. 9. For using the data warehouse  Without the metadata support, user cannot get an information every time they needed(user create their own ad hoc report).  Today data warehouses are much larger in size, wide in scope.  User critically need metadata.
  10. 10. For building the data warehouse(extraction team)  Need to know the structure and data content in the data warehouse.  Mapping and data transformations.  Logical structure of data warehouse database.
  11. 11. For administering the data warehouse  Impossible to administer the data warehouse(size)  Large no of questions and queries.  Cannot administer without answers for these questions.  Metadata must address these issues.
  12. 12. List of questions relating to data warehouse
  13. 13. Who needs metadata?  Without metadata, Datawarehouse is like such a filling cabinet without information.  Go through the image column(it address the our question)
  14. 14. Like a nerve center  Metadata placed in a key position and enables communication among various processes.
  15. 15. Why metadata is essential for IT  Development and deployment of data warehouse is joint effort between users and IT staff.  Technical issue-IT primarily responsible design and ongoing administration.  Metadata essential for IT  beginning with the data extraction and ending with information delivery.  It drives and record the each processes.
  16. 16. Summary list of process in which metadata is significant for IT  Data extraction  Data transformation  Data scrubbing  Data staging  Data refreshment  Database design  Query report and design
  17. 17. Automation of DWH tasks
  18. 18. Types by Functional Area  Classify and group in various way-some by usage and who use it  Administrative/End-user/Optimization  Technical/Business  Development/usage  In the data mart/At the workstation  Bank room/front room  Internal/External
  19. 19. Functional Areas  Data Acquisition  Data stroage  Information delivery
  20. 20. Data Acquisition  DWH process related to following functions. Data extraction Data transformation Data cleaning Data integration Data staging
  21. 21. Data aquisition
  22. 22. Data stroage  Data loading  Data archiving  Data management  Use metadata in this area for full data refresh and load.
  23. 23. Information Delivery  Report generating  Query processing  Complex analysis Mostly this are meant for end-user. Metadata recorded in processes of other two areas. It also record OLAP-the developer and administrators are involved in this processes.
  24. 24. Business METADATA  It connect business with DWH.  Business users need more than other users.  Business metadata is like a roadmap.  Tout guide-managers and analysis.
  25. 25.  Must describe the contents in plain language giving information in business teerms.  Example The name of data tables (or) individual element must not be cryptic. The data item name-calc_pr_sle. You need to rename this as calculated-prior- month-sale
  26. 26. Business metadata Contd.,  Much less structured than technical metadata.  Textual documents, spreadsheets, and even business rules and policies not written down completely.
  27. 27. Examples of Business Metadata who Benefits?  Primarily benefits end-users. Managers Business analysis Power users Regular users Casual users Senior managers/ junior managers
  28. 28. Technical Metadata  IT staff- Development and Administration of the data warehouse.  Who Benefits? Project manager Data warehouse administrator Metadata manager Database administrator Business analyst Data quality analyst