Normalization is the Process of Organizing the  data in an efficient manner.Really Normalization evolves from the Database optimization perspective.Really a good Database design solves the 30 % of the Database Performance Issues.IT reduce redundancy of Data.Normally we are doing

3 levels of normalization

First Normal Form (1NF)

First normal form (1NF) sets the very basic rules for an organized database:

  • Eliminate duplicative columns from the same table.
  • Create separate tables for each group of related data and identify each row with a unique column or set of columns (the Primary key).

Second Normal Form (2NF)

Second normal form (2NF) further addresses the concept of removing duplicative data:

  • Meet all the requirements of the first normal form.
  • Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
  • Create relationships between these new tables and their predecessors through the use of foreign Keys.

Third Normal Form (3NF)

Third normal form (3NF) goes one large step further:

  • Meet all the requirements of the second normal form.
  • Remove columns that are not dependent upon the primary key.

Difference Between Union all and Union

Many People know answer for this , but some people are there who are new into this,

What is UNION?

UNION is used to join two related set of data.UNION will give a distinct result ie; it

will avoid duplicates.How ever  the UNION  is bit slower due to distinct sort.



UNION ALL is also used to join two related set of data.UNION ALL will not Provide  a distinct sort.So it is very fast than UNION