Which of the following keys toggles between Insert mode and Overtype mode?

The condition expression1 || expression2 evaluates to false when ________________.

a) expression1 is true and expression2 is false b) expression1 is false and expression2 is true c) both expression1 and expression2 are true d) both expression1 and expression2 are false

Under what conditions might such an index be used?

We discussed the choice of indexes to optimize the execution of the nested query (12.1) and pointed out that a clustered index on Teaching with search key CrsCode would not be considered. It might, however, be used in optimizing the execution of the equivalent, non-nested query ``` SELECT C.CrsName, P.Name FROM Professor P, Teaching T, Course C WHERE T.Semester=’S2003’ AND P.Department=’CS’ AND C.DeptId = ’MAT’ AND P.Id = T.ProfId AND T.CrsCode=C.CrsCode ```