One of the most powerful applications of computers is the capability to store, organize, and retrieve large quantities of data. An organized collection of data is referred to as a database. The programs designed to manipulate databases are known as database management systems, commonly abbreviated as DBMS.
The purpose of databases is to make large amounts of information easier for humans to understand. Databases do not necessarily require the use of a computer. You probably already maintain several databases without even knowing it! Any time you keep track of information with some type of organized system, you are managing a database. Your calendar, personal phone book, and 'to do' list are all databases, even if you commonly write them with pencil (or crayon!) The telephone book is a database. Any time you keep a list of any sort, you are forming a sort of database. Databases have been an important information management tool since written language began.
Keeping track of information by hand has some shortcomings. Written lists can get very unwieldy if you have more than a pageful of entries. This problem is compounded if the information is not organized in some fashion like alphabetic order. This process of sorting is very tedious when done by humans. Anyone who files papers in an office knows how easy it is to misplace files when humans are responsible for keeping them in alphabetical order. Every time a new document is created, it must carefully be placed in the right spot. If it is ever 'taken out' and not replaced properly, it may never be found again.
The searching process can also be difficult. Looking up a word in a dictionary or a number in a phone book can be a frustrating experience if the word or name you are looking for is not spelled as you expected. Finally, these manual systems of organization can be quite clumsy when we want to find information in more than one way. For example, if you have a person's name, and you want their phone number, you can go to the phone book to find it. But what if you have the phone number or address, and not the name? A traditional phone book is almost completely useless for this kind of problem. In old detective shows, there were books printed by the phone companies for this type of purpose, but most people did not have access to them. If you think about it, the "find a person from a number" book would contain exactly the same information as a traditional phone book, just organized in a different order. It was necessary to recreate the entire database just to allow this amount of flexibility. If we wanted to be able to search for the name of a person with a certain address, we would need yet another entire book of the same size. With paper databases, it is impossible to search by more complex criterion, such as "tell me all the people that live on Poplar Street."