SQL & PL/SQL
Submitted by rleishman on Fri, 2007-03-02 18:25
One glance at my golf clubs would be enough to determine that I'm a terrible golfer. The pitching wedge is dirty. Nine-iron: dirty. Same with the eight, seven and six irons. Five, four and three irons are fairly clean. Woods: pristine. I play percentage golf (actually 110%, if you count penalties); I figure a 5-iron 150 meters down the fairway is a better bet than a 3-wood 200 meters into the trees.
So I've got a golf bag with 2 clubs that I paid for but never use. Madness? Well no, not really; but then I'm not paid to play golf. Can you imagine a professional golfer never using the driver? It wouldn't happen.
Can you picture an Oracle programmer never using the most powerful join method available? No? Get a mirror.
Submitted by rleishman on Sun, 2007-02-18 03:31
Benjamin Disraeli, circa 1870 wrote:
Never complain and never explain.
Disraeli was a lot of things, but Oracle Programmer was not amongst them. To be fair, perhaps he wasn't talking about Explain Plan?
SQL is a goal-oriented language. Unlike procedural languages, we tell the database what we want rather than how to get it. Oracle's Cost Based Optimizer comes up with an execution plan that is hopefully the most efficient way to resolve the query, but for many reasons it will often choose a sub-optimal plan.
Submitted by rleishman on Thu, 2007-02-08 23:48
A common complaint in SQL is that "it runs in 5 seconds in SQL*Plus, but takes hours in Production. Why?"
The reason is because SQL*Plus and most GUI SQL tools display rows as soon as they are fetched. In this way, you can
SELECT * FROM big_big_table and it will display the first 20 or so rows in the table in a fraction of a second, then go back for more. The SQL is not really finishing in seconds; if you timed how long it took to retrieve every row, you'd see that it takes just as long as in Production.
Submitted by rleishman on Sun, 2007-01-28 00:21
Where were you in 1990? Nelson Mandela was being freed from Victor Verster Prison after 26 years behind bars, Saddam Hussein was starting the Gulf War by invading Kuwait, and Tim Berners-Lee was inventing the World-Wide-Web at CERN in Geneva. Me? In 1990, I was writing an insurance system in Oracle SQL*Forms v2.3.
Submitted by Kevin Meade on Thu, 2007-01-11 12:58
So a buddy of mine, Ray, asked me for some examples of how data could be returned from a PL/SQL procedure. After a short discussion and some fiddling in SQL*Plus, we produced a neat document with some easy examples of what he could do. I still don't know how he is hooking this up to his coding tools, but it is a good demonstration of alternatives for manipulating sets of rows so I figured I'd post it. Hope someone besides Ray finds it useful. Ray's original question was "Kev, is there a way to return data from PL/SQL code so I can use it like a set of rows?". If you are an advanced PL/SQL developer you probabely already know this stuff but then again, it might be worth a five minute look for you.
Submitted by Kevin Meade on Sun, 2006-10-29 23:29
I don’t want to learn XML. I don’t want to learn XPATH. I don’t want to learn XQUERY. I don’t want to learn XSLT. I don’t want to learn XSQL. I don’t want to learn XSU. XDB has some way cool stuff. But to-date, I have been pretty successful in not learning things I don’t want to learn. So you might think that when the time came for my databases to start sharing data via a XML transport, I would be in trouble. Fortunately, God gave me at least a few smarts when he loaded me up with laziness. In this article we will discuss one way to move XML formatted data in and out of Oracle using what we already know: object views, instead of triggers, collections, and PL/SQL packages.
Submitted by gojko on Sat, 2006-10-28 14:05
A few days ago, while hunting for a bug in PL/SQL code, I stumbled upon the strangest way to write NULL. If the e-mail address parameter was empty, the genius who wrote this PL/SQL procedure set it to , then compared it with ten lines below, in order to log a problem. I really don't know what is it about NULL that scares people so much, but over the years I got used to occasional -1 and 0, or even 'EMPTY'. However, this is the first time I ran across Donald.
Submitted by Kevin Meade on Sat, 2006-10-21 12:57
If I had to recommend THE one most exploitable skill to have for an Oracle Developer or DBA, it would have to be HOW TO PLAY GOLF. I have observed few other talents give regular Mary and Joe, greater access to people from all levels of the corporate world. You will meet everyone from the janitor, to management elite without the fear or intimidation that we sometimes feel in these circles. For some reason, on the fairway all are equal; the only things that matter are your swing and your handicap. Alas, I never learned to play golf, so I must settle for imparting an actual job skill. And for that, my best first choice would be SQL FROM SQL.
Submitted by gojko on Sun, 2006-10-15 16:45
Accessing the database from the outside world basically comes down to two options - direct querying or executing stored procedures. Procedural access is often chosen for the wrong reasons - making maintenance significantly harder.
Submitted by Natalka Roshak on Mon, 2006-10-02 00:37
One handy new feature of 10gR2 is its vastly expanded ability to do case-insensitive sorts and compares (a subset of its expanded ability with other special sorts and compares, such as special linguistic sorts).