Transcript Document

Chapter 21
Information Integration
21.2 Models of Information Integration
Presented by: Kai Zhu
Professor: Dr. T.Y. Lin
Class ID: 220
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There are several ways that
databases or other distributed
information sources can be made to
work together.
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Three most common approaches:
Federated databases.
Warehousing
Mediation
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Federated databases:
Simplest architecture for integrating
several databases is to implement
one-to-one connections between all
pairs of database.
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Data Warehouses:
In the data warehouse integration
architecture, data from several
sources is extracted and combined
into a global schema.
The data is then stored at the
warehouse, which looks like an
ordinary database.
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Mediators:
A mediator supports a visual view, or
collection of views, that integrated
several sources in much the same
way that the materialized relations in
a warehouse integrate sources.
21.3 Wrappers in
Mediator-based System
Templates for Query Patterns:
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Use notation T=>S to express the
idea that the template T is turned by
the wrapper into the source query S.
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Wrapper Generators
The wrapper generator creates a
table holds the various query
patterns contained in the templates.
The source queries that are
associated with each.
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Filter
Have a wrapper filter to supporting
more queries.
Thank you