List 4 reasons for creating a database?

Answer 1

1) The data is Archival in nature

There is no real point in creating a database to calculate your tax returns, however there may be a point in storing all of those tax returns to look at further down the line or extract trends from.

2) The data is related to itself

Think of it as an Account and Transaction, if you were filling out an Excel spreadsheet with Customers and Transactions, you would end up filling out that customers name repeatedly, allowing for repeated mistakes on their details.

I would be better if that customer had a number attached to his details, and that number was attached to the transactions, that way you would only have to change the information in one location as the number would still link those two sets of data.

3) Limiting User Error

A relational system as mentioned in (2) would limit user error, since only one piece of information needs to be changed; limiting Update, Addition and Deletion errors alongside removing redundancy (All those repeated names take up space).

4) Storage is becoming a problem

A paper based system can take up a vast quantity of space, and what may end up as three floors of an office full of filing cabinets could quite happily reside on a database somewhere.

5) Relevant information need to be extracted quickly from the data

Whatever information you store, generally speaking a manager somewhere will one day turn around as say 'Well how many of X did we get on average a week from customer Y in year Z?'.

If at this point your staring at a paper based system or an excel spreadsheet you just earned yourself a large project to find out these statistics, in a relational format that query is exactly what it is; a question to the database that can be developed quickly and used repeatedly, you even have the X, Y and Z part of that question prompt for user input and let them select what they want.

6) You require multiple users to work on the data

It's hard for 7 departments of a company to share a piece of paper; they could photocopy it, but what if they all want to change it at the same time?

Databases have a method of locking records and releasing them when a user is done with them, some databases forgo this and place timestamps on every record for when they were last updated.

This means that every department would be able to work on Customer X's file without risking multiple overwrites.

7) Speed is important

You're sat looking at a room full of customer data and someone asks you to find a customer and seven items relating to them, which is faster; looking though them all or entering that customers surname and bringing up a complete record of that person.