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Using an index to answer queries

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• Prelude: database definition
  • Database of movies:

    Movie( title, year, length, genre, studioName. producer)

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  • Suppose, we have:

    A secondary index on studioName A secondary index on year

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• Use index to answer queries
  • Sample query:

    Find movies made by Disney (Dis) in the year 2005

    Process query as follows:

    Find all pointer to records satisfying studionName = Dis: Find all pointer to records satisfying year = 2005: Compute the intersection: