Chapter 14: Minimizing Universe Maintenance

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As the number of universes in your deployment increases, there are a number of ways you can minimize universe maintenance. As users access multiple universes, built by different designers, you need to ensure that the interface is as consistent as possible. Linked universes may help with this. For large-scale deployments, you will want to establish a test environment, either through a test repository or a test universe domain. Finally, with so much meta data built in to the universe, extracting meta data from an ETL tool may minimize your maintenance efforts.

Linked Universes

Linked universes allow a designer to build one master universe called the kernel that then is used to build a subsequent universe called a derived universe. Companies generally use linked universes in one of several ways:

  • A central universe designer builds a reference universe that contains common dimension classes that then get linked to other universes. In the derived universes, a second designer can add universe-specific tables. For example, in Figure 14-1, the tables and corresponding classes and objects for Time, Products, and Customers exist in the kernel universe. The designer for the Sales universe links to the Kernel to use these common classes and objects. The Sales designer hides classes that sales users do not need (Accounts, Employees) and adds new tables to the derived universe (SALES_FACT). This approach can drastically reduce implementation and maintenance efforts, while ensuring a consistent universe interface across multiple universes.

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    Figure 14-1: Linked universes help ensure consistent dimensions across universes.

  • A central universe designer maintains one kernel universe that contains all the star schemas in the data warehouse; business unit designers then create smaller derived universes that are focused on their individual user group (Figure 14-2). The business unit designer may hide many classes.

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    Figure 14-2: Linked universes allow universe creation to be decentralized yet still consistent.

  • A derived universe can contain links to more than one kernel universe, so you may also have two small kernel universes that then link to larger derived universes. This approach is good for decentralized development, but unless your company follows some strict design principles, the derived universe may contain duplicates and/or you may find it hard to build a cohesive-looking derived universe. The problems faced with this kind of model are similar to the ones faced when trying to build a central data warehouse from independent data marts.



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Business Objects(c) The Complete Reference
Cisco Field Manual: Catalyst Switch Configuration
ISBN: 72262656
EAN: 2147483647
Year: 2005
Pages: 206

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