slides19 - Schedule Today Mar 14(TH x Data Warehouses Data...

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Winter 2002 Arthur Keller – CS 180 19–1 Schedule Today: Mar. 14 (TH) Data Warehouses, Data Mining. Project Part 7 due. Mar. 16 (Sa) Final Exam. 12–3PM. In class.
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Winter 2002 Arthur Keller – CS 180 19–2 Warehousing The most common form of information integration: copy sources into a single DB and try to keep it up-to-date. Usual method: periodic reconstruction of the warehouse, perhaps overnight.
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Winter 2002 Arthur Keller – CS 180 19–3 OLTP Versus OLAP Most database operations are of a type called on-line transaction processing ( OLTP ). Short, simple queries and frequent updates involving one or a small number of tuples. Examples: answering queries from a Web interface, recording sales at cash-registers, selling airline tickets.
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Winter 2002 Arthur Keller – CS 180 19–4 Of increasing importance are operations of the on-line analytic processing ( OLAP ) type. Few, but very complex and time-consuming queries (can run for hours). Updates are infrequent, and/or the answer to the query is not dependent on having an absolutely up-to-date database. Example: Amazon analyzes purchases by all its customers to come up with an individual screen with products of likely interest to the customer. Example: Analysts at Wal-Mart look for items with increasing sales at stores in some region. Common architecture: Local databases, say one per branch store, handle OLTP, while a warehouse integrating information from all branches handles OLAP. The most complex OLAP queries are often referred to as data mining .
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Arthur Keller – CS 180 19–5 Star Schemas Commonly, the data at a warehouse is of two types: 1. Fact Data : Very large, accumulation of facts such as sales. Often “insert-only”; once there, a tuple remains.
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This note was uploaded on 02/21/2011 for the course CS CS 180 taught by Professor Dr.arthur during the Fall '01 term at The University of Akron.

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slides19 - Schedule Today Mar 14(TH x Data Warehouses Data...

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