The Relational Model

Relational Model





Relational Model for databases, highlighting the Key.

The image is of two tables, one storing "login," "first name," and "last name." Another table stores "login" and "phone number." The image illustrates using a unique key to link a phone number to a first and last name.

Image created Sodipodi.

Data items organized as a set of formally described tables from which data can be accessed or reassembled in many ways without having to reorganize the database tables. Each table (sometimes called a relation) contains one or more data categories in columns. Each row contains a unique instance of data for the categories defined by the columns.

Source:
http://en.wikipedia.org/wiki/File:Relational_Model_2.jpg