It deals with typical data quality problems, such as the object identity
problem (Cohen, 1999), errors due to mistyping, and data inconsistencies
between matching records. AJAX provides a framework wherein the logic of
a data cleaning program is modeled as a directed graph of data transformations
that start from some input source data. AJAX also provides a declarative
language for specifying data cleaning programs, which consists of SQL statements
enriched with a set of specific primitives to express mapping, matching,
clustering, and merging transformations. Finally, a interactive environment is
supplied to the user in order to resolve errors and inconsistencies that cannot
be automatically handled and support a stepwise refinement design of data
cleaning programs. The theoretic foundations of this tool can be found in Galhardas,
Florescu, Shasha, and Simon (1999), where apart from the presentation
Data Warehouse Refreshment
Copyright ?© 2007, Idea Group Inc. Copying or distributing in print or electronic forms without written permission
of Idea Group Inc. is prohibited.
of a general framework for the data cleaning process, specific optimization
techniques tailored for data cleaning applications are discussed.
The Potter??™s Wheel system (Raman & Hellerstein, 2001), is targeted to provide
interactive data cleaning to its users.
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