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

70) In E-R Diagram derived attribute are represented by

71) Cross Product is a:

72) An instance of relational schema R (A, B, C) has distinct values of A including NULL values. Which one of the following is true

73) Consider the join of a relation R with relation S. If R has m tuples and S has n tuples,then the maximum size of join is: