   What is a Database?
  What’s the best way to describe a database to someone that has never used one or know what one does?For the longest time I couldn’t really grasp why you would want to use a database to organize and deliver your data in an application.  One programmer I knew described a database as a way to organize a large text file, which didn’t really make much sense to me.After working with SQL for about 6 months I now know how a database works and what it does.  So now whenever someone asks me what a database is, I would tell them this.  “A Database is essentially a structured file system that allows a user to do complicated searches based on data in the database or data provided by the user.  The reason why we use a database instead of the native file system of a computer is because a database can store, search and retrieve data in a more efferent manner.  The reason why we don’t use a database as a file system is because databases consume more resources than a file system thus making it less practical as a file system for an ordinary PC.”It’s a little wordy but I think it makes it clear what a database is and what it does.  Real database machines typically do use a lot of resources, and even in some cases manage hard drives with out the use of an OS file system.   
  If i had to explain what is database, i'd probably just give a link to wikipedia: Database (i'd tell to read the intro, because after that - it gets a bit technical). And if there are any questions after he reads it - i'd do my best to answer them.   ;You might also mention in your description - that a 'Database' is often run using an independant/seperate program (ie- a library or even an entire Application/Service) which was created as a general (reuseable) solution to 'database' type problems (storing/retrieving/searching information).The 'database' can now have its data accessible to other programs that use the same database mechanism.From my experience, a program saving/loading/searching its own data on files isnt usually refered to as a 'database'.   A program may integrate an existing 'database' mechanism.   