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Data Warehouse. Week 8 Introduction of Data Warehouse Multidimensional Analysis: OLAP. Data Warehouse. Integrated, Subject-Oriented, Time-Variant, Nonvolatile database that provides support for decision making. Characteristics of Data Warehouse. Integrated Centralized
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Data Warehouse Week 8 Introduction of Data Warehouse Multidimensional Analysis: OLAP Fox MIS Spring 2011
Data Warehouse • Integrated, Subject-Oriented, Time-Variant, Nonvolatile database that provides support for decision making
Characteristics of Data Warehouse • Integrated • Centralized • Holds data retrieved from entire organization • Time Variant • Flow of data through time • Projected data • Non-Volatile • Data never removed • Always growing • Subject-Oriented • Optimized to give answers to diverse questions • Used by all functional areas
Multidimensional Analysis:OLAP (Online Analytical Processing)
Online Analytical Processing (OLAP) • Advanced data analysis environment • Supports decision making, business modeling, and operations research activities • Characteristics of OLAP • Use multidimensional data analysis techniques • Provide advanced database support • Provide easy-to-use end-user interfaces • Support client/server architecture
Multidimensional View of Sales • Multidimensional analysis involves viewing data simultaneously categorized along potentially many dimensions
Data Warehouse Modeling: Star Schema • Data-modeling technique • Also called star-join schema, data cube, or multi-dimensional schema • The simplest style of data warehouse schema. • The star schema consists of one or more fact tables referencing any number of dimension tables • Maps multidimensional decision support into relational database • Yield model for multidimensional data analysis while preserving relational structure of operational DB • Facts • The fact table holds the main data. It includes a large amount of aggregated data, such as price and units sold • Dimensions • Dimension tables, which are usually smaller than fact tables, include the attributes that describe the facts. • Attributes