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PL/SQL Feed

Oracle PL/SQL (Procedural Language/Structured Query Language) resources, news, and support articles.

The Database Design Quiz in Numbers

The first quarter of the database design quiz on the PL/SQL challenge finished last week. Being a numbers geek, here’s some facts and figures from how it’s gone so far:

To Buy or Not to Buy: FIJI Natural Artisan Water

Here's why FIJI Water thinks we should buy "their" water:

In Fiji, rainfall filters through volcanic rock over hundreds of years, adding vital minerals that give FIJI Water its unique and refreshing taste. The water collects in an ancient artesian aquifer deep within the earth, where it is protected from external elements. It's the way nature intended water to be. Untouched.

Here's why I think we should NOT buy this water:

Analytic View of Functional Dependency

A recurring theme of this blog is that there is more to a relation than being merely a set of tuples. First, a relation is an object which obeys certain rules. The structure of this object is less important as long as it satisfies relational algebra axioms. Second, in previous post we have learned that relations are systems of constraints. The idea that a relation can be viewed as a set of constraints has been promoted in the 90s by Paris Kanellakis. Our intuition, however, is that by narrowing scope to equalities we can leverage powerful machinery of algebraic geometry.

Relations as Finite Varieties

It is common wisdom that database field is firmly grounded in the two math disciplines: predicate logic and set theory. However, neither logic nor set theory are dominant math subjects. Just counting tags at mathoverflow.net can give rough idea of the importance of an individual math topic, and it is evident that algebraic geometry governs the math world. This field is so rich that it spawned new sub-fields, such as category theory.

Oracle 12c Offset & Rows

Oracle Database 12c provides a limit syntax in SQL for a query with the following clause:

Excel PowerPivot & DAX

I’ve worked with every release of Microsoft Excel, and I know it takes effort to keep up to date with certain releases. Clearly, the Data Analysis eXpression (DAX) Language introduced in Excel 2010 went unnoticed by many, which was sad. DAX is truly a powerful extension to the analytical and modeling approaches in Microsoft Excel.

23 December Quiz Now Available

For those of you checking for news on the PL/SQL Challenge site via the blog (and not the plsqlchallenge twitter account, which we encourage you to follow):

The quiz for 23 December is now being displayed properly.

Our apologies for the invalid image error and display.

All answers submitted prior to 13:45 were removed, so you can take the quiz again without simply guessing.

If we end up with 475+ answers for the day, I probably will not void the results.

Improving Website Performance: An Update

I announced earlier this week that I was suspending all work on new features until we improved the performance on the site.

Since then we have done the following:

Christmas Break

update sqlfail
set next_post_date = date '2014-01-06';
I’m taking a bit of a break over Christmas while I spend time with my daughter and her grandparents. Thanks to everyone who follows this site, hope you have a great Christmas/festive time and 2014 is everything you hope for. :)
In the meantime, there’s a message hidden in the SQL below for you (note, you’ll need to run this on 11.2.0.2 to guarantee it works):

OUT Parameter Trick

Raja asked a question but unfortunately, I was buried in the final aspects of the write of the new Oracle Database 12c PL/SQL Programming book. He wanted to know how to pass an object type as an OUT-only mode parameter from a procedure.

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