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What are aggregate tables?

April 26, 2017aggregate tables

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What are aggregate tables?

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To explain what aggregate tables are, let’s consider a simple star schema. The star schema has a single fact table Sales, two measure columns (units and dollars) and four dimension tables (Product, Mfr, Customer, Time, and Customer). On top of this star schema, we create the following multidimensional model: • Cube [Sales] has two measures [Unit sales] and [Dollar sales] • Dimension [Product] has levels [All Products], [Manufacturer], [Brand], [Prodid] • Dimension [Time] has levels [All Time], [Year], [Quarter], [Month], [Day] • Dimension [Customer] has levels [All Customers], [State], [City], [Custid] • Dimension [Payment Method] has levels [All Payment Methods], [Payment Method] Most of the dimensions have a corresponding dimension table, but there are two exceptions. The [Product] dimension is a snowflake dimension, which means that it is spread across more than one table (in this case Product and Mfr). The [Payment Method] dimension is a degenerate dimension; its sole attribute is