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A file manipulation command that extracts some of the records from a file is called

  • A.SELECT
  • B.PROJECT
  • C.JOIN
  • D.PRODUCT

Answer: A

Correct answer: SELECT

Select extracts rows that satisfy a condition - the horizontal slice. Project takes columns, join combines two relations on matching values, and product pairs every row with every row. (Confusingly, SQL’s SELECT statement performs projection as well; the relational operator named select is what the WHERE clause does.)

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