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<h1>Relational Database Model</h1><p>Relational data model is based on the concept of
a relation or a table. An entity is presented by a tuple or row. Table fields
are used to describe entity attributes (Model, Year, Pilot, Age in the example
below). Each entity should be identified by a primary key, which is constructed
from the data in the row. In the example below the key is created by combining
the values of "Model" and "Year" fields.</p><p><img src="Relational_Database_Model/Table.Jpg"/><br></p><p>In addition to the primary key relational data
model supports foreign keys: a primary key of one table used in another table
to allow joining of data. In the example above the primary key from the Pilots
table ("Pilot" field) is used in the Cars table; it allows to associate a car
and a pilot.<br>
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This revision (1) was last Modified 2007-06-02T19:32:31 by Tetyana.
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