One of the most popular Oracle certifications is 1Z0-047. SQL skills are incredibly useful in the IT industry, and being recognized as an expert in this field adds value to a résumé. That said, this is a difficult exam to pass, and I've heard some people admit to failing it on one or more occasions in certification forums. This article is intended to give you an idea of what will be required of you on the test so that you can plan accordingly.
The Oracle Education website lists all of the subjects that will be covered in the 1Z0-047 exam. There are other Oracle SQL capabilities that aren't on that list, but they won't show up on the test. Oracle Education's topic listings are continuously up to date. There are 38 topics on the SQL Expert test that are also covered on the 1Z0-051 SQL Fundamentals exam. These aren't covered in the expert test. Anything from them is fair game, although the majority of the questions will be drawn from the thirty-eight 1Z0-047-specific subject areas. If you're attempting this certification, you should already be familiar with basic SQL.
Almost every question in 1Z0-047 will involve a SQL statement, as you might expect. Sometimes the question will include a statement, and you'll have to choose from a list of options that explain what it means. Other questions will explain a desired outcome, and the responses will be a variety of SQL statements. You must select the SQL that best suits the request. The SQL tends to be longer and heavier on joins than what is covered in the SQL Fundamentals exam. You must be familiar with ANSI join syntax in order to take the test; the legacy Oracle syntax will not be used. You must also be able to parse SQL in your brain and figure out what it will perform. The majority of the SQL in this test will run without errors, but the results will not be as expected. This is significantly more difficult to discover than SQL that just fails when executed.
You must be well-versed in SQL syntax and be able to distinguish between what is and is not possible. Some of the questions will almost certainly contain SQL that is absolutely legal but is phrased in a way that makes you think it isn't. There are several valid approaches to write SQL statements that are rarely used. A HAVING clause placed before a GROUP BY clause is an example. This will work, but I've never seen SQL written in this manner. You'll also need to be able to recognize popular SQL functions and predict the results of DDL statements. You'll need to be conversant with a number of topics, including those that even seasoned SQL developers only utilize sometimes if at all. I've been writing SQL for seventeen years and have yet to utilize a ROLLUP or CUBE query in a professional setting. Once in a while, I'll employ REGEXP functions and hierarchical queries. To do well on the test, you'll need to know all of these.
There will be 70 multiple-choice or multiple-answer questions on the SQL Expert test. The passing score is currently 66 percent. There is no partial credit for the multiple-choice questions. It's just as bad to leave a question unanswered as it is to answer one badly, so don't leave any question unanswered, even if it means picking a letter at random. The number of exhibits in 1Z0-047 is significantly more than the average for Oracle certification examinations. They're primarily entity relationship diagrams that give context to the tables that the SQL in the query refers to. Even though entity relationship diagrams are not listed as a test topic, you must be able to interpret them. Many of the diagrams are quite complicated, and only a small section of each figure is actually necessary to answer any given issue. Furthermore, using the exhibit was not required for more than half of the questions on the test when I took it. The questions with exhibits ask you to look at the diagram before answering the question, however I recommend reading the question first. You might be able to skip the exhibit entirely, which will save you time. If you do need to look at it, you'll know exactly what information you're looking for. Look over all of the answers when dealing with questions when the response is one or more SQL statements. Almost always, you can find at least one that has a defect that disqualifies it as a correct response. Once you've ruled out one or two of the options, you may focus your efforts on the remaining options.
1Z0-047 is designed to ensure that only individuals with a deep mastery of SQL pass, and it succeeds admirably. On this test, you'll notice that the incorrect answers aren't obvious, and the correct answer isn't obvious. The SQL and accompanying exhibits are rather complicated, and many of the questions are designed to test your knowledge rather than your ability to memorize facts. Before you schedule the exam, make sure you understand all seventy-six topics. Good luck with the exam.