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Relational Operations (cont)

Two "dimensions of variation":
  • which relational operation   (e.g. Sel, Proj, Join, Sort, ...)
  • which access-method   (e.g. file struct: heap, indexed, hashed, ...)
Each query method involves an operator and a file structure:
  • e.g. primary-key selection on hashed file
  • e.g. primary-key selection on indexed file
  • e.g. join on ordered heap files (sort-merge join)
  • e.g. join on hashed files (hash join)
  • e.g. two-dimensional range query on R-tree indexed file
As well as query costs, consider update costs (insert/delete).