Oracle PL/SQL Quizzes
In the past week (5 September - 9 September), 822 Oracle technologists were busy submitting 2,465 answers to quizzes and exploring the library of past quizzes. Here are the PL/SQL quizzes played in that period:5 September 2011: PLS_INTEGER and its subtypes will raise an overflow error if the value assigned to it is greater than 2147483647; SIMPLE_INTEGER will "wrap around" to -2147483648 and "count up" from there.
550 Players ** Avg. Correct: 72% ** Avg. Time: 219 seconds ** Rating: 4 stars
6 September 2011: PL/SQL offers a number of ways to retrieve multiple rows from a dynamic SQL query; OPEN-FOR is especially helpful when you plan to use the BULK COLLECT clause as you fetch, but also want to use the LIMIT clause to manage memory consumption.
658 Players ** Avg. Correct: 78% ** Avg. Time: 321 seconds ** Rating: 4 stars
7 September 2011: It is often necessary to continue executing your application code, even after an error is raised. Both SAVE EXCEPTIONS and LOG ERRORS allow you to do this when errors occur in DML statements. It is important, however, to be aware of the differences between the two, and choose the feature that best matches your requirements.
642 Players ** Avg. Correct: 63% ** Avg. Time: 282 seconds ** Rating: 4 stars
8 September 2011: Oracle will perform implicit conversions under many circumstances. Often, such conversions will have no or minimal impact on performance or correctness. Generally, however, it is best to perform explicit conversions to ensure correct behavior of your programs.
632 Players ** Avg. Correct: 6% ** Avg. Time: 567 seconds ** Rating: 4 stars
9 September 2011: When you need to check for and match on a NULL value in your CASE statement or expression, you need to use a searched, not simple, CASE format.
560 Players ** Avg. Correct: 81% ** Avg. Time: 191 seconds ** Rating: 4 stars
SQL Quizzes
Between 13 August - 9 September, Oracle technologists played these SQL quizzes:13 August 2011: Whenever your column values may contain NULLs, you should be very careful in how you construct your SQL statement to take this into account.
494 Players ** Avg. Correct: 89% ** Avg. Time: 894 seconds ** Rating: 4 stars
20 August 2011: If a condition refers to an aggregate function, put that condition in the HAVING clause. Otherwise, use the WHERE clause. It is always recommended to include ORDER BY Clause in order to sort records. Don't rely on possible implicit sorting of GROUP BY Clause.
517 Players ** Avg. Correct: 70% ** Avg. Time: 627 seconds ** Rating: 4 stars
27 August 2011: The NULL value is not a value like "abc" or 123. It actually means "there is no value" and is handled very differently by Oracle from any non-NULL values.
526 Players ** Avg. Correct: 79% ** Avg. Time: 301 seconds ** Rating: 4 stars
3 September 2011: Use of analytic function COUNT with the RANGE clause to count records with values within defined ranges.
523 Players ** Avg. Correct: 82% ** Avg. Time: 2070 seconds ** Rating: 4 stars
Oracle Application Express Quizzes
Between 13 August - 9 September, Oracle technologists played these APEXquizzes:13 August 2011: Use validation functions for plug-in items so that you can build validations into the plug-in, and avoid writing validations on each page where a relevant item appears. Use built-in APEX procedures to communicate errors to the user.
237 Players ** Avg. Correct: 62% ** Avg. Time: 755 seconds ** Rating: 4 stars
20 August 2011: Dynamic actions are one of most exciting features of APEX 4. They allow actions to be performed that previously would have been done with jQuery. As well as the built-in dynamic actions you also have the option of entering your own Javascript. Some issues that may arise when incorrectly coding dynamic actions are outlined below as well as the best pratices.
232 Players ** Avg. Correct: 56% ** Avg. Time: 983 seconds ** Rating: 4 stars
27 August 2011: By using a combination of application processes, page groups and conditions you can
conditionally hide or show items in the application. Page groups allow the applications pages to be easily grouped and subsequently identified as to which pages they are related too and what part of the application they are used in. It helps to understand the different syntax that can be used within a condition. It highlights two different methods of setting a condition with a "PL/SQL Expression" and the "Value of Item in Expression 1 = Expression 2".
241 Players ** Avg. Correct: 62% ** Avg. Time: 1939 seconds ** Rating: 4 stars
3 September 2011: This question will teach users how the APEX data dictionary views can be used to find out information about the applications in the workspace.
226 Players ** Avg. Correct: 59% ** Avg. Time: 913 seconds ** Rating: 4 stars
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