08-16-2017, 09:56 PM
Virtual Database Technology for Distributed Database
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introductionn
In a large modern enterprise, it is almost inevitable that different portions of the organization will use different database management systems to store and search their critical data. Competition, evolving technology, mergers, acquisitions, geographic distribution, and the inevitable decentralization of growth all contribute to this diversity. Yet it is only by combining the information from these systems that the enterprise can realize the full value of the data they contain.
Transparency
If a federated system is transparent, it masks from the user the differences, idiosyncracies, and implementations of the underlying data sources. Ideally, it makes the set of federated sources look to the user like a single system. The user should not need to be aware of where the data is stored (location transparency), what language or programming interface is supported by the data source (invocation transparency), if SQL is used, what dialect of SQL the source supports (dialect transparency), how the data is physically stored, or whether it is partitioned and/or replicated (physical data independence, fragmentation and replication transparency), or what networking protocols are used (network transparency)
Heterogeneity
Heterogeneity is the degree of differentiation in the various data sources. Sources can differ in many ways. They may run on different hardware, use different network protocols, and have different software to manage their data stores. They may have different query languages, different query capabilities, and even different data models
A high degree of function
IBM's federated capability provides users with the best of both worlds: all the function of its rich, standard-compliant DB2 SQL capability against all the data in the federation, as well as all the function of the underlying data sources.