Relational Databases  «Prev 

Different Types of Normalization

Database Normalisation is a technique of organizing the data in the database. Normalization is a systematic approach of decomposing tables to eliminate data redundancy and undesirable characteristics like
  1. insertion,
  2. update and
  3. deletion
anamolies. It is a multi-step process that puts data into tabular form by removing duplicated data from the relation tables.
Normalization is used for mainly two purpose,
  1. Eliminating reduntant (useless) data.
  2. Ensuring data dependencies make sense i.e data is logically stored.

1) There are 3 different values stored in a single column, the table is not considered normalized.

2) In the first normal form, information items have been put into their own columns

3) The second normal form introduces a unique value that describes each row, and only that row. Typically the unique identifier has nothing to do with the data in the table, it is usually a counter.

4) In third normal form, the information within each table is not duplicated, and the tables are tied together by the Item name.