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diff --git a/doc/unit-7.md b/doc/unit-7.md index f6c1d3a..523d758 100644 --- a/doc/unit-7.md +++ b/doc/unit-7.md @@ -4,6 +4,13 @@ * Read "Chapter 9: Basic concepts of data warehousing" +* data warehouse: a subject-oriented, integrated, time-variant, nonupdateable collection of data used in support of management decision-making processes. + +* subject oriented: organized around key subjects. e.g. customers, patients, students, products, and time. +* integrated: data housed in the data warehouse are defined using consistent naming conventions, formats, encoding structures and related characteristics gathered from multiple sources. +* time-variant: data in the data warehouse contain a time dimension so that they may be used to study trends and changes. +* nonupdateable: loaded and refreshed from operational systems but cannot be updated by end users. + ## Section 2 - Data Warehouse Architectures and OLAP Tools Read the Chapter 9 sections: @@ -22,3 +29,14 @@ Read the Chapter 9 sections: * describe the process used to generate derived data; * describe the star schema, as used in data marts; * present a variety of tools and techniques that are used to query, analyze, and visualize the data stored in data warehouses and data marts. + +### Data Warehouse architectures + +* three-level architecture: bottom up, incremental approach +* three-level architecture: top-down approach emphasis on coordination and an enterprise-wide perspective. + +1. extract data from internal/external sources. (daily, weekly, monthly) +2. transform data. +3. load data. + +I think I just fell asleep for several pages. |