Last Week at the PL/SQL Challenge

For those of you who still may not have registered, explored and played quizzes at the PL/SQL Challenge, here's a recap of last week's PL/SQL quizzes:

In the past week (15 August - 19 August), 790 Oracle technologists were busy submitting 2,376 answers to quizzes and exploring the library of past quizzes. Here are the PL/SQL quizzes played in that period:

15 August 2011: When you want to declare an associative array with an integer index, the datatype of the INDEX BY clause must be BINARY_INTEGER or any of its subtypes. You should, as a rule, always use PLS_INTEGER unless you have some specialized requirement.
              528 Players ♦ Avg. Correct: 64% ♦ Avg. Time: 221 seconds ♦ Rating: 4 stars

16 August 2011: Make sure that you are both aware of all possible built-in functions and that you use them in a way that optimizes both performance and maintainability.
              634 Players ♦ Avg. Correct: 73% ♦ Avg. Time: 444 seconds ♦ Rating: 4 stars

17 August 2011: ALL_PROCEDURES gives you information about the subprograms (procedures and functions, both schema-level and within packages) on which you have EXECUTE authority.
              633 Players ♦ Avg. Correct: 80% ♦ Avg. Time: 203 seconds ♦ Rating: 4 stars

18 August 2011: Use SAVEPOINT to define a point in your session's transaction to which you can rollback. This feature allows you to only partially rollback changes in your session.
              624 Players ♦ Avg. Correct: 70% ♦ Avg. Time: 273 seconds ♦ Rating: 4 stars

19 August 2011: You can compare a collection to NULL, but keep in mind that associative arrays will always evaluate to NOT NULL - even if they do not contain any data. Nested tables and varrays are NULL until initialized.
              591 Players ♦ Avg. Correct: 68% ♦ Avg. Time: 213 seconds ♦ Rating: 4 stars