Do you speak my language: D is for Database, debug, DNS

D is for Database, debug, DNS... In fact, I am a bit short of Ds. Anyway, my choice has to be database.

What is a database?

This may seem like an odd question, but it is surprising how many people really don't know. Some people think that a database is a spreadsheet (as in Excel spreadsheet). Yes, you can use a spreadsheet as a database, but it not a good idea.

A database is a way of storing and collecting data in a computer. The data is organised in to records (you can think of these as identical forms that are filled in), with each record containing fields to hold the data (think of fields as a set spaces or boxes on the form). In a spreadsheet records are usually stored in the rows, and the fields in columns.

There are three great advantages of storing data in a database:

1. The data can be very easily and rapidly searched.
2. (And this is the critical one) Normalisation.
3. One source to rule them all (apologies to Lord of the Rings).

Searching

Databases are designed to be searched. Spreadsheets are not.

It is also possible to construct very complicated searches across databases where you may be searching for the occurrence of a piece of information only in specific fields, and under specific conditions (e.g. only give me records where the score is over 80% and the test was completed after the end of the month). This again is not possible with a spreadsheet.

Normalisation

There are five levels of normalisation, but that is not really important and most databases rarely go beyond level 3.

One of the key steps in normalisations is the 'mininisation of redundancy'. What this means is that the data is organised such that there are no repeats. That is, data only appears once, and if that data is used again then it is referenced using a unique identifier that doesn't change. The advantage here is if a change needs to be made to the data then only one change has to be made, and this change is reflected in all places the data is used. This is something that is not easy to do with a spreadsheet as it may mean the one piece of information has to be changed in multiple places on the sheet.

One source

This again is a real advantage of using a database over a spreadsheet.

Databases tend to reside on a server (see S in this series) and are accessed with a client (see C - Do you speak my language: C is for Cloud Computing, Computer, C, client, cron job, compile, compress, cookie, code, command line interface). With a database on a server it means that ever user is accessing the latest version of the data, and there isn't that nagging worry that the spreadsheet you are using is out of date.

The other Ds in the list:

Debug: To remove bugs (not moths - see B - Do you speak my language: B is for Blog, Backend, Basic, Backbone, Backup, beta software, bash, bug) from a computer (see C - Do you speak my language: C is for Cloud Computing, Computer, C, client, cron job, compile, compress, cookie, code, command line interface)

DNS: Domain Name Server - a server (see S) that changes the name of a website in to an IP address (see I in this series) so that the server can be located on the Internet.

Protein: 2X2E

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