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The Projection Operation (cont)

The projection operation needs to:

  1. scan the entire relation as input
    • already seen how to do scanning
  2. remove unwanted attributes in output tuples
    • implementation depends on tuple internal structure
  3. eliminate any duplicates produced
    • two approaches: sorting or hashing


Example of task 2:

[Diagram:Pics/scansortproj/project-one-tuple.png]