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Leaving a Metadata Trail

Leaving a Metadata Trail. Chapter 14. Defining Warehouse Metadata. Data about warehouse data and processing Vital to the warehouse Used by everyone. Metadata. The Key to Understanding Warehouse Information. Specifies data location Manage data Aids use of information Describes the data

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Leaving a Metadata Trail

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  1. Leaving a Metadata Trail Chapter 14

  2. Defining Warehouse Metadata • Data about warehouse data and processing • Vital to the warehouse • Used by everyone Metadata

  3. The Key to Understanding Warehouse Information • Specifies data location • Manage data • Aids use of information • Describes the data • Documents the development process • Provides a record of changes • Records enhancements over time

  4. Metadata Users IT developers Metadata repository ETT End user Operational Warehouse End users

  5. Types of Metadata • End user: - Key to a good warehouse - Navigation aid - Information provider • ETT: - Maps structure - Source and target information - Transformations • Operational: - Load, management, scheduling processes - Performance

  6. Developing a Metadata Strategy • Define a strategy to ensure high-quality metadata useful to users and developers. • Primary strategy considerations: - Define goals and intended use. - Identify target users. - Choose tools and techniques. - Choose the metadata location. - Manage access to the metadata. - Manage access to the metadata. - Integrate metadata from multiple tools. - Manage change.

  7. Defining Metadata Goals and Intended Usage • Define clear goals. • Identify requirements. • Identify intended usage. Metadata

  8. Identifying Target Metadata Users • Who are the metadata users? - Developers - End users • What information do they need? • How will they access the metadata?

  9. Choosing Metadata Tools and Techniques • Tools - Data modeling - ETT - End-user query and analysis • Database schema definitions • COBOL copybooks • Middleware tools

  10. Choosing the Metadata Location • Usually the warehouse server • Possibly on operational platforms • Desktop tool with metalayer Metadata repository External sources Operational Data sources Warehouse End users

  11. Managing the Metadata • Managed by the metadata manager • Maintained by the metadata architect • Standards produced by the metadata architect Metadata repository External sources Operational Data sources Warehouse End users

  12. Integrating Multiple Sets of Metadata • Multiple tools may generate their own metadata. • There are many metalayer integration issues. • Metadata exchangeability is desirable.

  13. Managing Changes to Metadata • Different types of metadata have different rates of change. • Consider metadata changes resulting from refresh cycles.

  14. Examining Types of Metadata • ETT metadata • End user metadata Metadata repository End user ETT Warehouse

  15. ETT Metadata • Business rules • Source tables, fields, and key values • Ownership • Field conversions • Encoding and reference table • Name changes • Key value changes • Default values • Logic to handle multiple sources • Algorithms • Time stamp External sources Extraction Staging file Operational data sources

  16. Extraction Metadata • Space and storage requirements • Source location information • Diverse source data • Access information • Security • Contacts • Program names • Frequency details • Failure procedures • Validity checking information External sources Extraction Staging file Operational data sources

  17. Transformation Metadata Transform • Duplication routines • Exception handling • Key restructuring • Grain conversions • Program names • Frequency • Summarization External sources Staging file Operational data sources

  18. Transportation Metadata • Method of transfer • Frequency • Validation procedures • Failure procedures • Deployment rules • Contact information Transport Metadata repository ETT External sources Transport Transport Staging file Warehouse Operational Data sources

  19. End-User Metadata 739516 1816 666 17.62 • Associate the metadata description • Analogous to Oracle Data Dictionary views Metadata repository End user Warehouse

  20. Example of End User Metadata

  21. More End-User Metadata Information • Location of fact and dimensions • Availability • Description of contents • Algorithms for derived and summary data • Owners of data and telephone number Metadata repository End user Warehouse

  22. Historic Context of Data • Supports change history • Maintains the context of information Operational Warehouse Metadata repository Structure Content 95 96 94 97 98

  23. Types of Context • Simple: - Data structure - Naming conventions - Metrics • Complex: - Product definitions - Markets - Pricing • External: - Economic - Political Warehouse 95 96 94 97 98

  24. Additional Metadata Content and Considerations • Summarization algorithms • Relationships • Stewardship • Permissions • Pattern analysis • Reference tables

  25. Metadata Management Tools • Carleton • Evolutionary Technologies • Hewlett Packard • Informatics • Oracle Designer • Platinum Technology • Prism Solutions • Sagent

  26. Common Warehouse Metadata Design and Administratioon

  27. Common Warehouse Metadata Future Discover Warehouse Builder Common metadata Oracle8i Server Express Server

  28. Summary This lesson discussed the following topics: • Definitions • Integration • Contents • Storage • Creation • Selection • Tools

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