Project Operator

• Simple scanning method often used if no index:

  Read tuple
  
  While more tuples
  Output specified attributes
  Read tuple

• Duplicate removal may be necessary

  • Partition output into separate files by bucket, do duplicate removal on those
  • May need to use recursion
  • If have many duplicates, sorting may be better

• Can sometimes do index-only scan, if projected attributes are all indexed

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