Bringing our focus to today's technology one thing immediately springs to mind: we have to deal with an inordinate amount of data like nowhere else in history. Nearly everything that we produces a measure of easily verifiable data, whether it is at work through productive metrics or as consumers of products and services that can tallied, allowing this very data to be tabulated and used for noticing patterns and trends over a period of time. Data is the smallest unit of meaning, while information is compiled data that serves a certain purpose, while knowledge is information that can be used to gain an end within a context.
In short, Data is the representation of "facts" or "observations" whereas information refers to the meaning thereof (according to some interpretation). Knowledge, on the other hand, refers to the ability to use information to achieve intended ends. The transformation of data into information and further into knowledge depends largely on advanced systems capable of doing this processing at the same time that it allows human analysts to check the data and make sense of it for future decision-making processes. These systems are what we call databases.
Database systems are nowadays an essential part of our life in modern society, causing all of us to be regular users of at least one major database throughout the course of our existence, be it library systems, bank transactions, grocery store purchases, hotel/airline reservations.
Traditional database applications are built to rely heavily on rigidly-structured textual and numeric data. As database technology continues to make forays into unknown territory to reach out to a larger number of users, it becomes clear that a new db system for analysing data should suffice to glean information from data which structured data applications can't handle. Hence nowadays we have multimedia databases and geographic databases (involving maps and satellite images).
Keeping a large amount of data and conducting regular and agile queries on them calls for a system specialised for just this: the proper handling of massive information. Thence we need a dbms (database management system) to refer to just about any collection of related data, which also have the following properties:
definition: specifying data types (and other constraints to which the data must conform) and data organization
construction: the process of storing the data on some medium (e.g., magnetic disk) that is controlled by the DBMS
manipulation: querying, updating and report generation
sharing: allowing multiple users and programs to access the database "simultaneously"
system protection: preventing database from becoming corrupted when hardware or software failures occur
security protection: guarding db against malicious or unathorised access.