DATABASE DESIGN

                                 

           

DATABASE DESIGN

            The overall objective in the development of database technology has been to treat data as an organizational resource and as an integrated whole. DBMS allow data to be protected and organized separately from other resources. Database is an integrated collection of data. The most significant form of data as seen by the programmers is data as stored on the direct access storage devices. This is the difference between logical and physical data.

NORMALIZATION 

                Normalization is a technique of separating redundant fields and braking up a large table in to a smaller one. It is also used to avoid insertion, deletion and updating anomalies. All the tables have been normalized up to the third normal form. In short the rules for each of the three normal forms are as below.

   First Normal Form

                        A relation is said to be in 1NF if all the underlying domain of attributes contain simple individual values.

Second Normal Form

 

                        The 2NF is based on the concept of full functional dependency. A relation said to be in 2NF if and only if it is in 1NF and every non-key attribute is fully functionally dependent on candidate key of the table.

                                                               Third Normal Form

     

                          The 3NF is based on the concept of transitive dependency. A relation in 2NF is said to be in 3NF if every non-key attribute is non-transitively.