Sunday, 15 November 2009

Relational Databases

Databases are the most efficient way to store large amounts of information. They emerged in the corporate world when it slowly became obvious that different departments were storing the same information in different places and, perhaps even worse, in different ways.

Databases allowed organisations to store all of that information in one place. Each company created a single central database which was then accessible to different parts of the organisation. Various different people and various different applications were all able to use it. This was far more efficient and opened up lots of new possibilities for businesses.

The data in databases is stored in tables. Most databases consist of a series of linked tables. Each piece of data is placed in relation to the other bits of information in the database, hence the name relational.

When you are creating a database it is important to start of by thinking about the relationships between the different pieces of information that you want to store. This is called the entity relationship model.

Users find information in a database using a software called Database Management Systems (DBMS). Most databases are managed using Structured Query Language (SQL). This is the language that the user has to use to 'ask' the database to find a particular piece of information.

The following is an example of an SQL Query.

select title, year_published, isbn, pubid from titles where year_published >= 1980
order by year_published asc;

This would give you the title, year of publication, ISBN and PubID for any titles in the database which were published after 1980. The list would be in chronological order.

Cascading Style Sheets

Cascading Style Sheets are a tool which allows Web designers to make their websites more attractive. They allow designers to specify how they want the Internet browsers to present their sites.

HTML was never meant to be used to give browsers detailed instructions about the appearance of sites. It dates back to a simpler time when the Web was mostly used for exchanging academic information. Attractive presentation wasn't as important as it is today, when a website needs to try hard to get itself noticed. When that shift first became apparent people did try to use HTML in order to make their sites more interesting. They came up with some creative ideas but they lost the elegant simplicity and universality of well-crafted HTML. The Web needed a better way to let designers control the appearance of their sites. Cascading Style Sheets were the solution.

As Richard Butterworth said in his lecture on this topic a style sheet is simply "a set of instructions that identify the style to be used in publishing a manuscript". (Lecture 6: Markup and Cascading Style Sheets.) A Cascading Style Sheet is a set of instructions for the Internet browser. It tells the browser how to present a particular webpage or group of pages. In essence this is the same as the style sheets that publishers and newspapers use to specify how their documents should be printed.

The clever thing about CSS is that it is very versatile. For example it can be used to efficiently present a number of web pages in the same style. The information only needs to be read once.

On the other hand CSS can also be used to present the same web page in a variety of styles.

The Zen Garden website is a thought provoking showcase for the latter technique. Visitors can choose to see the site in a huge range of different styles. Each style created by a different designer, each one of them striving to demonstrate exactly how versatile Cascading Style Sheets really are.

I have used CSS to control the appearance of my website. I make no claim to be ready for Zen Garden, but it it is clearly a very useful tool.


XML stands for eXtensible Mark up Language. Despite its name it arguably isn't a language at all. It might be more helpful to think of it as a metalanguage; a set of rules for creating your own language.

It was created by the World Wide Web Consortium (W3C). The idea was to create a way for people to make their own mark up language. Thus giving them much greater freedom to use data effectively by allowing them to create mark up languages for their own specific purposes.

Document Type Definitions are central to the process. They are used to tell other people about the rules that apply to a particular XML document. This allows them to know exactly what that document is doing. It also opens up the possibility that they could adapt that piece of XML for their own purposes.

The Use of XML in Healthcare Informatics

Healthcare Informatics is an important growth area for Librarians and other Information Professionals. Broumphrey and Harrison have investigated the use of XML in this field. They believe that it will help healthcare services to deal with patients information much more effectively. They claim that, "XML has taken the business world by storm .... it is likely that it will have a similar effect on the healthcare industry." (Broumphrey and Harrison, 2000).

Friday, 6 November 2009


Computers would be much less enjoyable to use, and much less useful if they couldn't display graphics. The World Wide Web might have started out as a purely text based system but imagine how impoverished our experience of it would be if it had stayed that way.

To give just one example the writing section of my website would be much less interesting without the Earth Vs the Flying Saucers movie poster. Note that I used a URL to link to an image at

Thankfully computer graphics are part of our everyday lives, but how many of us know how they work?

There are two different ways of storing graphics digitally. Raster and vector.

1. Raster

The raster system uses a grid. The computer stores information about the contents of each square in the grid.

2. Vector

The vector system stores each bit of information about the picture in relation to the other bits of information and to a notional starting point.

Graphics Formats

The three main graphics formats are PNG, JPEG and GIF. Each format has its own strengths and weaknesses.

1. GIF is perhaps the most widely used of the three. It is perfect for reasonably simple graphics. As I Librarian I might use it to put a logo or a simple drawing on a Library website.

If it was appropriate I could also use it to add some animation to the site. GIF is the only one of these three that can be used for that purpose. It is the cheapest way to add animation to a website.

GIF's main disadvantage is that it isn't suitable for photos or other complex pictures. It has a very limited palette. A GIF file can only support 256 colours.

2. PNG was intended to be a replacement for GIF. It is generally used for for similar kinds of image: logos, line drawings and other simple pictures. Its main advantages over its older rival are that it is better at compressing colour and it supports more colours. However it is important to note that PNG doesn't support animation. That suggests that it won't replace GIF.

On a Library website PNG would be used in a similar way to GIF.

3. JPEG is the standard way of storing photos digitally. It is also widely used for similar very complex images. The main reason for this is that it has a far larger range of colours than its rivals. An impressive 16 million plus to GIF's mere 256.

If I was running a library website I would use JPEG for any photos that I wanted to put up on the site; photos of Library events for example.

Lossy or Lossless

When dealing with graphics it is important to draw a distinction between lossy and lossless compression algorithms. GIFs and PNGs are lossless. If you try to make the files smaller then your images will lose colour and clarity but the data will be retrievable. It will be possible to restore them to former glory. JPEG on the other hand uses a lossy system. If you try to make a JPEG smaller then it will reduce the quality of the image and it will get rid of the data. You won't be able to restore the picture. It's important to save a backup copy of a JPEG file before you resize it.

Please see my website for an illustration of the lossy nature of JPEGs.

The Internet & The World Wide Web


The Internet. The biggest thing to happen to information since the printing press; an unmissable business opportunity; the future of democracy; a place for people to come together and exchange ideas; a place where the storehouses of knowledge have finally been thrown open to everyone.

Technical innovation often gets people excited but it is hard to think of a recent invention that has caused quite as much excitement as the Internet and the World Wide Web. How big an impact have they really had?

A Thought Experiment

Lets try a thought experiment. Put any cynicism to one side for a moment and imagine that the Web and the Net have been uninvented. As of now they no longer exist. How would your life change? Ignoring the global economic crisis which would make the credit crunch look like a golden age lets look at the impact on our everyday lives.

Work and study in a Webless world would require organisational skills that have atrophied in the children of the digital age. Tasks that the Web has made almost effortless would suddenly become much harder. Resources and information that we are used to having at our fingertips would suddenly be unattainable.

What is the outcome of our thought experiment? Personally I find that my cynicism is replaced by a sense of awe that anyone managed to get anything at all done before the Web was invented.

History & Definitions

The Internet has come a long way. It started out as the American Military's answer to the question of how to stay in touch after a Third World War. It quickly moved from being an interesting experiment in military communications to being a very useful way for academics to share information. It was the Web which really brought the Internet out into the open, allowing it to escape academia and take on roles that its inventors never imagined.

People often confuse the Internet and the Web but actually they are different. The Internet is the infrastructure, the actual network of computers. The Web is a system of hyperlinked documents which allows us to navigate and move around that network. The analogy that Richard Butterworth used in his lecture was that "the Internet is a road and the world wide web is a type of car that you can drive around on that road." (Lecture 3: The Internet and the World Wide Web).

HTML and My Website

The World Wide Web relies on HTML. It is the markup language which is used to tell browsers how to display webpages. In a world which is increasingly dependent on the Web, gaining a basic understanding of HTML is a a very good idea. With that in mind I have created this very simple website.