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| Some frequently asked questions about SQLzoo
Why do you have those horrible adverts?Sorry about that. The point of this site is to teach, not to make money. It's no excuse, but I do use the income for good works, mostly sending me to conferences in hot countries. The advert-free version is http://sqlzoo.net/noads/ Which Engines are working?The engines run a variety of SQL implementations on a number of different machines. You can see from the table below which of the engines is working right now. Please report any broken or slow engines to ajcumming@gmail.com The following links may repair broken or slow engines: Dawn (SQL Server) Priya Ryka Justin Ernest Tilly Who runs this site?Andrew Cumming is a lecturer at Napier University in Edinburgh, Scotland, UK. Can I shake his hand/buy him a drinkNext time you are visiting Edinburgh, UK you can shake his hand at the Tollcross State Circus which meets on Monday, 7pm to 9pm in Tollcross primary school. You can buy him a drink afterwards, in the Blue Blazer, Spittal Street; a pint of 80 Shilling please. How does this site work?The source of the main tutorial section is stored in xml files such as:
http://sqlzoo.net/s2/home.xml
. These files contain an xml format that is close to html but has a handful
of additional tags (such as The xml files are processed by an xsl style sheet http://sqlzoo.net/cmn/0.xsl which translates them into proper html. The proper html includes javascript to take care of issues such as:
Additionally the xml files are translated into various languages and stored in language directories such as http://sqlzoo.net/de/home.xml. The translations are initially provided by Google - but can be edited by human translators. I maintain a "zoo" of SQL engines that process users SQL attempts. Why is it called SQLzoo?The animals of this zoo are SQL engines - one of each species. They have been caged and tamed. The public can poke, prod and gawp - the exhibits and the public are protected from each other. Andrew is the zoo keeper, he feeds them and shovels away the waste. Can I link to your site?Yes please do - link from as many places as possible. Link from your page, link from bulletin boards, ask for a link from any directories. If at all possible include the word Since you're asking - there's two kinds of link that bother me -
Neither of these do me any harm - but they don't do me any good either. Universities (including my own, Napier) should not use gated systems like this. Coolest incoming link: MIT Getting hold of SQLYou may wish to use your own SQL engine - the "connected" servers will inevitably have a variable performance.
The zip file gisq.zip contains all of the tutorial material. Obtaining the dataSample data used in SQL zoo has been collected from a variety of sources. While I'm happy for you to publicise sqlzoo as widely as possible you should not attribute the data to me. Some was collected from agencies without their consent some was adapted from the work of colleagues (or their colleagues). My only contribution has been to present it in a convenient format. The data is available in Microsoft Access format gisq.mdb SQL commands to create and populate the tables are available. The individual tables are available in tab delimited format. This can be imported into pretty well anything.
Notes for teachersThis material was designed to be used in supervised tutorials at Napier University. Teachers from other institutions are welcome to use it in any way they see fit, however I have a few requests/suggestions:
What happened to the CIA database?Prior to 2006 the early tutorials were based on data from the CIA World Factbook. The data now comes from the BBC Country Profiles pages. I use country data from the BBC web site. Their country profile pages include details of just under 200 countries. It makes fascinating reading. The CIA World Factbook is still a remarkable result, and the CIA should be congratulated for being one of the first authoritative resources on the the internet. In the early days of the internet most large organisations were worrying about how they could protect themselves from the internet. When I first took the data from the world factbook I associated the CIA with Mission Impossible and cool spy equipment. Since then the CIA is more associated with extraordinary rendition. They seem less cool. The CIA World Factbook also has some bizarre inclusions. The RAF base in Akrotiri in Cyprus is a place I love. While it may have the fire power of a small country it is not a country by any civil measure. AcknowledgementsThe red error messages that appear in tutorial one are generated in JavaScript from code developed by Emma Oram as part of her excellent MSc. project 2002. Readers should assume that errors or omissions in the data are mine and not the fault of following sources. Thanks are due to the following fine organisations:
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