Inside databases

Is Facebook an open book?
Absolutely not. There is no suggestion that Facebook and similar companies would sell your data or mine.

They will, without doubt, obey the data protection laws and abide by any additional assurances and promises they have given.

To do otherwise would be commercial suicide. However, there is surely a clear distinction between selling the data that belongs to an individual and selling aggregated information about trends in particular market segments about how people interact socially, and about how they influence each other.

And it is this (rather than the individual data) that may well be of commercial interest.

Ebay Gum
There is another side to this, so-called ‘behavioural’ data. At the same conference I talked to Oliver Ratzesberger, Senior Director of Architecture & Operations for Ebay, Inc.

Ebay collects information about what we buy on its site (obviously) but it al so monitors all of our actions which tell it how we buy and how we interact with the system and other Ebay customers.

He said that the value of the behavioural data is now more valuable to the company than the transactional data.

That single, simple statement speaks volumes about how the analysis of data is no longer simply about transactions, it is about us and how we interact – with websites, with companies and with each other. So bear that in mind next time you are tempted to hurl a heifer.

Keep it symbol
Stewart McGregor asked me about incorporating symbols into text and memo fields in Access 2007. He makes much use of symbols that aren’t part of the basic ASCII set , Ω, ∞, § and ©, for instance, and would like a way to keep these readily to hand so they can be typed in easily as part of a text entry.

The Autocorrect facility can be pressed into service here: not only can it be set to correct my habitual misspelling of ‘databse’ to ‘database’, it can also translate keystrokes into symbols. Given a little preparatory tweaking, you can type, say, ‘qq’ and have it instantly translated into © in the text you’re typing.

Click the Office button, select ‘Access options’ and choose ‘Proofing’. Under the ‘Autocorrect options’ banner, click the ‘Autocorrect Options...’ button. (In Access 2003 it’s Tools, Options, Spelling, Autocorrect Options.)

Depending on your system the ‘Replace’ and ‘With’ lists may either be empty or may already contain autocorrect options.

In the ‘Replace’ list type the keystrokes you want to be translated into ©: choose something that doesn’t appear much or at all in common usage. Double q or double y are examples, or letter-number combinations like w3.

In the ‘With’ column, insert the relevant symbol. Open the Character Map (Start, All Programs, Accessories, Program Tools), click on it and then on Select.

Flip back to Access and paste the symbol into the ‘With’ column and click Add. When you have finished, click Close and then OK to escape from the Access Options window.

Now when entering text into a text or memo field, whenever you type ‘qq’ plus a space (or if you move focus from that field) it will appear as ©.

An Autocorrect Options flash appears as the translation is made: clicking this lets you choose to return the text to read qq, to turn off the automatic translation, or to ‘Control Autocorrect options...’.

Selecting this takes you to the now-familiar screen where you can set up automatic corrections. Incidentally, if you type ‘qqr’ or ‘pqq’, for instance, the translation to the copyright symbol is not performed.

Also incidentally, the Autocorrect settings work across applications, so you can use the same keystrokes in Word and Excel to incorporate symbols.

SQL and Relational Theory: How to Write Accurate SQL Code
Chris Date is one of the guys who, with Ted Codd, developed and popularised the relational model. SQL is the language universally associated with the relational model.

That does not mean, however, that SQL is part of the model nor does it mean that these guys helped develop it. In fact, Chris Date has always been highly critical of the language, arguing that it is seriously flawed.

I have great respect for Chris Date and hold him in high regard, not least for his book ‘Introduction to Database Systems’ (Addison Wesley, 8th edition, ISBN: 978-0321197849) which is the classic work on relational databases.

However, I have always felt that he has been somewhat nihilistic in his unrelenting condemnation of SQL. The chance of mass adoption of an alternative language is non-existent and that leaves him as a voice in the wilderness complaining but never offering a viable alternative for the average database devotee.

All of which explains why this book is so great: Chris has taken a much more positive approach, saying that if you are going to use SQL – and of course you and I will because there is no alternative – here’s how to use it effectively.

Explanations and examples are given with recommendations that will teach you ‘How to Write Accurate SQL Code’. It is not only a fascinating book but also immensely valuable because ultimately Chris is right: SQL is flawed and people do get into trouble using it.

We needed someone of Chris’s intellect and experience to show us the way, and he has done so. This book is essential reading for those already experienced with SQL and who are becoming aware of its limitations. It is published by O’Reilly, ISBN 978-0-596-52306-0