12 - OLAP

12 - OLAP - OLAP (Online Analytical Processing) Excerpt...

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1 USC - CSCI585 – Fall 2010 – Farid Parvini OLAP (Online Analytical Processing) Excerpt from OLAP Presentation by Cyrus Shahabi
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2 USC - CSCI585 – Fall 2010 – Farid Parvini Content Introduction to Decision Support Multidimensional Databases Focus Application: OLAP Prefix-Sum Data Cube Dynamic Data Cube Iterative Data Cube Wavelet-based approaches Compact Data Cube ProPolyne
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3 USC - CSCI585 – Fall 2010 – Farid Parvini Introduction To Decision Support Organizational decision making requires a comprehensive view of all aspects of an enterprise, and many organizations have therefore created consolidated data warehouses that contain data drawn from several databases maintained by different business units, together with historical and summary information.
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4 USC - CSCI585 – Fall 2010 – Farid Parvini Introduction To Decision Support Decision Support data models have three important data analysis application areas: Data warehouses are large repositories that integrate and abstract data from several sources in an enterprise for analysis. Online analytical processing (OLAP) systems provide fast answers for queries that aggregate large amounts of detail data to find overall trends. Data mining applications seek to discover knowledge by searching semi-automatically for previously unknown patterns and relationships in multidimensional databases.
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5 USC - CSCI585 – Fall 2010 – Farid Parvini Introduction To Decision Support
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6 USC - CSCI585 – Fall 2010 – Farid Parvini Toward OLAP There are many characteristics of decision support queries that make traditional SQL systems inadequate: The conditions in the WHERE clause often contain many AND and OR conditions. OR conditions, in particular, are poorly handled in many relational DBMSs. Applications require extensive use of statistical functions such as standard deviation, which are not supported in SQL- 92. Many queries involve conditions over time or require aggregating over time periods. SQL-92 provides poor support for such time-series analysis.
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7 USC - CSCI585 – Fall 2010 – Farid Parvini Toward OLAP (cont) A very common operation is aggregating over one or more attribute. The following queries are typical: Find the total sales. Find total sales for each city. Find total sales for each state. Find the top five products ranked by total sales. The first three queries can be expressed as SQL queries over multiple tables, but the last query cannot be expressed in SQL (although we can approximate it if we return answers in sorted order by total sales, using ORDER BY).
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8 USC - CSCI585 – Fall 2010 – Farid Parvini Introduction To OLAP Online analytical processing (OLAP) systems provide fast answers for queries that aggregate large amounts of detail data to find overall trends.
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12 - OLAP - OLAP (Online Analytical Processing) Excerpt...

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