Databases are an essential part of any web application. Databases allow us to store information about our clients, users, products, sales, and virtually anything else you could possibly want to store. Using a relational database management system (RDBMS), we can define how various pieces of data relate to one another.



For example, we may have a table in our database that contains a list of all our registered users, their names, addresses, email addresses, usernames, and passwords. We may also have a table that contains a record of every sale we make and which use bought it. Having these two tables relate to one another allows us to look at our sales table and see that John Doe bought a widget for $100 on the first of January last year. In a properly designed database, we give our user a unique ID and then store that ID along with the sale for that user. Now instead of putting the user?s name, address, and email address in our sales record, we can simply tie the sales record to the user record so we only have to store the user?s name and other information once.



This is just a very small and basic example of how a database can be used. Databases are used in many different ways including the web, desktop applications, and client/server applications to name a few. Once you have a database designed, though, you must have a way to access it. This is why it?s important to learn how to create data sources for use in your ColdFusion applications.