An intro to databases

Where the presentation layer governs the user's interaction with an ebusiness system and the application layer coordinates its behaviour, it's the data layer that brings an ebusiness system to life -- structured information defines entities and relationships representing the actual business and affairs the system exists to support.

Here, to introduce the topics of databases and business intelligence, we will review some key terms.

What is data?	In a broad sense raw data are numbers, characters, images or other outputs from devices which convert ideas or physical objects into symbols. Raw data is a relative term; data processing commonly occurs by stages, and the "processed data" from one stage may be considered the "raw data" of the next
What is information?	Data on its own has no meaning, only when interpreted by some kind of data processing system does it take on meaning and become information. People or computers can find patterns in data to perceive information, and information can be used to enhance knowledge. Since knowledge is prerequisite to wisdom, we always want more data and information. But, as modern societies verge on information overload, we especially need better ways to find patterns.
What is an entity	An entity is something that must be distinctly represented in an eBusiness system. People, organizations, accounts, products and services, customers, orders, and suppliers, are all examples.
What is persistence?	For our purposes think of persistence as the characteristics of continuity, reliability, and connectedness. Persistence of data and business logic, over time, and throughout an ebusiness process, even as it spans multiple software components, or even as a system is stopped and restarted, is critical to creating a seamless and stable system.
What is a Database?	A database is an information set with a regular structure
What is a Relational Database Management System (RDMBS)?	A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users.  See: relational databases.
What is the relational approach to managing data?	When managing data using the relational approach information is represented by data values arranged in mathematical relations. The data is operated upon by means of a relational calculus and algebra. The relational model permits the database designer to create a consistent logical model of information, to be refined through database normalization

More terms:

http://hea-www.harvard.edu/MST/simul/software/docs/pkgs/pgsql/glossary/glossary.html

http://www.canberra.edu.au/~sam/whp/db-terms.html

See:  Building Business Intelligence