Data Integrity And Normalization

OVERVIEW:

Data Integrity:

Database integrity refers to the correctness and consistency of data. It is another form of database protection. While it is related to security and precision, it has some broader implications as well. Security involves protecting the data from unauthorized operations, while integrity is concerned with the quality of data itself. Integrity is usually expressed in terms of certain constraints which are the consistency rules that the database is not permitted to violate. Following two are the most important constraints in relational database:

(i)       Entity Integrity: is a constraint on primary values that states that no attribute of a primary key            should contain nulls.
(ii)      Referential integrity: is a constraints on foreign key values that states that if a foreign key                  exist in a relation, then either the foreign key value must match the primary key value of some            tuple in its home relation or the foreign key value must be completely null.

Normalization:

Normalization is the process of converting complex data structures into simple and stable data structures. It is based on the analysis of functional dependence.
             In other  words, Normalization is a technique for reviewing the entity/attribute lists to ensure that attributes are stored "where they belong".

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