The Relational Model

[attachment=16505]

Introduction


Relational Database
a) Attributes and Domains
b) Tuples
c) Relations and Their Schemes
d) Relation Representation
e) keys
f) Relationships
g) Integrity Rules
Relational Algebra
Relational Operation


Attributes : Attribute is correspond to fields.

Fields: Fields are refer to smallest item of data that are used to capture some specific property of the object.
Sets of attributes are denoted by uppercase letters from the end of the alphabets such as :NAME,AGE,ADDRESS


Types of Attributes


Domain :The set of allowed values for each attribute is called the domain of the attribute

Attribute values are (normally) required to be atomic; that is, indivisible

The special value null is a member of every domain

The null value causes complications in the definition of many operations