Week 11: Clear

I really enjoyed this weeks lecture. It just seemed to me its the 'in' thing right now. Database management is huge in technology world or even in computer world. A database management system is a suite of software applications that together make it possible for people or businesses to store, modify, and extract information from a database. Sound like something found only in bank vaults? It's not. You can find database management systems many places in your everyday life. That ATM that you get cash out of every week is a database management system. When you make flight reservations online, you're providing information that is entered into a database management system. Even the library that you or your children check out books from runs on a database management system.

On a more personal level, your personal computer can have its own database management system. You might have spreadsheets that contain mountains of data. Any time you fill up a spreadsheet with data and run queries to find and analyze data in different ways, you are accessing a database management system. And how do you view the data that is the result of a query? By looking at a report. Most database management systems have a reporting function that is the last step in the data manipulation process. After all, collating the data without looking at it won't get you very far.

One of the main functions of the database management system is doing the heavy lifting for you. In other words, you don't necessarily have to know exactly where all that data is in the system; as long as the database management system knows where it all is, it can deliver a report for you to peruse. This might not seem to matter if you're thinking of just your computer; but throw in a mainframe that contains reams and reams of data, and we're talking about a huge amount of information that can be stored any number of places within the mainframe system. The result is the same, though: a report that you can read, analyze, and act on. This functionality also extends to a multi-user database. Such a database management system under this scenario would allow you as one user to operate all functions within the database without having to know what other users are accessing the same database. One popular example of this kind of multi-user database is Microsoft SQL Server.



The database community has developed a series of guidelines for ensuring that databases are normalized. These are referred to as normal forms and are numbered from one (the lowest form of normalization, referred to as first normal form or 1NF) through five (fifth normal form or 5NF). In practical applications, you'll often see 1NF, 2NF, and 3NF along with the occasional 4NF. Fifth normal form is very rarely seen and won't be discussed in this article. It's important to point out that they are guidelines and guidelines only. Occasionally, it becomes necessary to stray from them to meet practical business requirements. However, when variations take place, it's extremely important to evaluate any possible ramifications they could have on your system and account for possible inconsistencies.

http://databases.about.com/od/specificproducts/a/normalization.htm
http://philip.greenspun.com/panda/databases-choosing
http://databases.about.com/od/administration/g/dbms.htm