Simple Pleasures…rlwrap and SQL*Plus Command Line editing on Linux

Fat, bald, likes a drink and a smoke. No, not me. That’s a description of Darren Lehman, the new coach of the Australian Cricket Team.
Sounds like a good bloke to me.
As a cricket fan, with the Ashes as the highlight of the sporting summer, I’m getting a horrible sense of deja vu.
If you read the press, Australian and English, you might be forgiven for thinking that the series is a foregone conclusion.
Yes, England should win, on paper. However, unless the groundsmen at the relevant venues have been doing something very innovative, the Tests themselves will be played on grass.
In order to take my mind off some of the more worrying parallels with this series and the one in 1989 – when Alan Border and a bunch of Aussie no-hopers demolished England 4-0 – I’ve been looking at one of those niggling little problems that I always mean to get sorted but never quite get round to.

Generally speaking, I much prefer Linux to Windows. There is however, on area where Windows has the upper hand.
When you’re working in SQL*Plus, Windows allows command line recall and editing by default. This feature is not present in Linux by default.
However, Linux, being Linux, there is a handy utility that can implement this functionality. It’s called rlwrap.
What I’m going to cover here is :

  • a recap of built-in SQL*Plus editing capabilities
  • Using rlwrap with SQL*Plus
  • The joys of TAB-Completion

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Oracle Float to Integer fun and Sachin Tendulkar

I recently spent some time working with Venkata, an Oracle programmer and keen cricket fan :

Venkata smiling the smile of a man whose team have won the cricket world cup twice more than...er...Wales.

Venkata smiling the smile of a man whose team have won the cricket world cup twice more than…er…Wales.

This post is about the fun and games involved in the bulk loading of data into Oracle – especially when it includes floating point values.
In Venkata’s honour, I’m going to explore this topic through the medium of the career of Sachin Tendulkar…

At this point it’s probably worth wandering off the point to explore some of the highlights of The Little Master’s career.

India’s tour of England in 1996 has been largely forgotten. However, it proved to be a watershed in our hero’s test career.
The first test of the series at Edgebaston was not untypical of the time – Indian batsmen skittled in conditions totally alien to them. The could only muster a paltry 219 in their second innings and none of them got beyond 18…apart from Tendulkar, ninth out for 122, made with a serenity that contrasted starkly with the chaos surrounding him.
It was in the very next match, at Lords, that India granted test debuts to two batsmen who themselves would prove quite useful over the years. Surav Ganguly marked the occasion with a century. Rahul Dravid fell an agonising five runs short of doing the same.
The fourth member of India’s vaunted middle-order announced himself in the next series we look at, against Australia.
Having been soundly beaten in the first test of the series, India came back the hard way in the second test.
VVS Laxmans 281 not out, with the not inconsiderable assistance of Dravid (180) and Harbhajan (13-196) became only the third team in the history of Test Cricket to win after following on. This against arguably the best team to have ever played the game who had their record winning streak of 16 consecutive tests ended somewhat emphatically.
The 2004/05 series against Bangladesh is included because Tendulkar’s highest test score (248 not out) was made in this series.
The 2009/10 series against South Africa is indicative of the journey that India made during the course of Tendulkar’s career.
At this time they were vying with South Africa for the status of the world’s leading test nation.

Back to the techie stuff. What I’m going to cover is :

  • What happens when you insert a floating point value into an INTEGER column
  • How you can overcome this using SQL*Loader
  • An alternative approach using external tables

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Old Dog, New Phone – Insert into multiple tables in a single statement

I got a new ( and possibly new-fangled) phone recently.
Having spent a suitably geeky amount of time exploring the new features of this slab of Android lovliness I did come across something which left me quite stumped… somebody rang me up on it.
Increasingly frantic tapping of the little green phone icon failed to result in me answering the call.
It was at this point that Deb took pity and explained in that ever-so-patient way people use to the hard of thinking, that I simply needed to swipe.
Needless to say, she’s not ever mentioned the incident again and would never dream of taking any opportunity to bring it up to elicit a laugh at my expense. Ahem.
It’s unfortunate that I also got a work phone recently and spent five minutes tapping the screen before I worked out that the Blackberry I was holding was not, in fact, a touch-screen device.
As the fast-paced world of consumer electronics passes by in an ever-increasing blur, I’m comforted by the fact that I can still learn something new.
For example, I was recently faced with a situation requiring me to load data from one table into two further tables, depending on certain criteria.
With the aid of my trusty netbook ( a form-factor that is apparently as outdated as it’s owner), I shall now demonstrate the wonder of the age that is the multi-table insert statement.
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An APEX Database Monitoring App for XE – Guilty GUI pleasures

Guilty pleasures. For some, it’s a “diet” burger with “diet” fries, washed down with a “diet” shake. Others have a penchant for Kurt Geiger shoes. “I’m Welsh and I’m worth it”, they may well say. It may even be that Def Leppard track nestled in your playlist between Coldplay and Oasis.

In programming terms, APEX seems to fall into this category for me. On the one hand, it’s a declarative development environment. This means that, unless you’re very careful, the application you write for it is not going to be too portable to other front-end technologies. But, oh, it’s so nice to be able to bang out a bit of SQL and/or PL/SQL, click my mouse in the right place, and have a nice GUI application drop onto my browser.

If you’ve decided to try the latest and greatest APEX version on your XE installation, you’ll notice that the default Database Welcome Page disappears after the upgrade.
Rather than hunting around for it, I’ve decided to knock up something a bit better…well, different.
So, if you’d like to know how to get some interesting configuration information out of the database…or just want the entertainment value of watching me blunder about in APEX then read on… Continue reading

ORA-02030 and invisible objects. The database bites back !

Being Luis Suarez’s agent must be an interesting job right now.
Maybe the man was a bit peckish.
Alternatively, maybe he’s resigned to the FA’s reluctance to introduce a mid-season break and was simply making his own arrangements for time off during the season.
Either way, this particular agent may well be trying to sign Luis up for an ad campaign for a popular brand of toothpaste.

Oracle DBA’s may sometimes have some sympathy with Suarez, although they’re more likely to end up chewing the desk in frustration, rather than their fellow DBA’s (unless the Christmas Party has really gotten out of hand).
Every so often, Oracle throws out an error that, on the face of it, makes absolutely no sense…
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How long is a (piece of) String. Cricketing Greats and the length function

My Dad gave me a book recently – the 100 Greatest Cricketers. As well as selecting what – in his opinion at least – were the 100 finest exponents of the game, the author also decided to rank them in order from 1 to 100.
At this point, for those who don’t know, I should perhaps explain that Cricket is one of those games given by the English to the rest of the world….to prove what sporting losers the English could be.
For any Australians reading, to whom this statement may ring hollow given their teams current travails, fret not. Historically, England’s brief ascendancy the battle for the Ashes tends to come to a juddering halt when least expected, usually in the form of a 4-0 thrashing ( think 1958-59, 1989).

Anyway, back to the book. Comparing players across different eras is hard enough – just how would you evaluate the relative merits of Sachin Tendulkar and Sir Jack Hobbs, for example ?
But comparing the relative merits of a batsmen and bowler who were contemporaries in the same team is equally problematic. Who is the greater cricketer out of Dennis Lillee and Greg Chappell, or Malcolm Marshall and Viv Richards ?

All of this brings to mind the saying, “how long is a piece of string”.
In SQL, at least, we do have an answer to this question…or do we ? Continue reading

Disabling the Oracle Diagnostic and Tuning Pack APIs – If you want something done, do it yourself

At last, we have reached the final episode of the Star Wars themed odyssey through the tangled web that is Oracle’s Diagnostic and Tuning Pack licensing.
Just as well really, Deb has flatly refused to give over any more evenings to my “research” – i.e. re-watching all of the films. Even the appeal of Ewan MacGregor’s Alec Guiness impression has now waned.
Just to recap then, so far I’ve looked at :

Now, finally we’re going to have a look at how we can minimize the chances of an errant select statement causing a whole heap of trouble.
Yes, we’re going to have a go at disabling access to the Diagnostic and Tuning Pack APIs without (hopefully), breaking anything.
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