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COMPUTER SOFTWARE APPLICATION - CITS



                                                            Example
           2  Second Normal Form (2NF)
                                                             Product ID        product         Brand
              In 2NF, the table must be in 1NF, and all non-
              key attributes (attributes that are not part of     1            Monitor             Dell
              the  primary  key)  must  be  fully  functionally
              dependent  on the entire primary key.  This         2            Monitor            Apple
              eliminates  partial  dependencies,  where           3            Scanner             HP
              non-key attributes are dependent on only a
              portion of the primary key.                         4            Head phone          JBL

           Product table following 2NF
           Products Category table:
                                                               Brand table:
            Product ID                       product           Product ID                     Brand
              1                   Monitor                         1                            Dell

                2                       Monitor                     2                        Apple
                3                       Scanner                     3                           HP
                4                 Head phone                        4                               JBL



           Products Brand table:
                    pb ID                   product ID                              brand ID

                     1                         1                                                1
                     2                         1                                                2
                     3                         2                                                3
                     4                         3                                                4


           3  Third Normal Form (3NF)
              In  3NF,  the  table  must  be  in  2NF,  and
              all  non-key  attributes  must  be  directly
              dependent  on the primary key.  This
              eliminates   transitive   dependencies,
              where  non-key  attributes  are  dependent
              on other non-key attributes.
              These three  normal forms  are the most
              commonly  used  and  usually  suffice  for
              many database designs. However, there
              are  additional  normal  forms  like  Boyce-
              Codd  Normal  Form  (BCNF)  and  Fourth
              Normal  Form  (4NF)  that  address  more
              complex scenarios of data dependencies
              and anomalies.

           Normalization  helps  improve  database
           design by:
           -   Reducing data redundancy, which in turn
              conserves  storage  space  and  ensures
              consistency.









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                              CITS : IT&ITES - Computer software application - Lesson 18 - 36
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