Sql server Basics

1.Sql server :- sqlserver is a database platform for large-scale online transaction processing(OLTP),it is also a business intelligence platform for dataintegration,analysis, and reporting solutions. 2.Normalization It is the process of organizing data into related table. To normalize database, we divide database into tables and establish relationships between the tables. It reduces redundancy. It is done to improve performance of query.

Steps of normalization:

First Normal form
Entities of the table must have unique identifier or entity key.
Second Normal Form
All the attributes of the table must depend on the entity key for that entity.
Third Normal Form
All attributes that are not part of the key must not depend on any other non-key attributes.

                                                                           (or)

Defination: Normalization is the process of reducing data redundancy and maintains data integrity. This is performed by creating relationships among tables through primary and foreign keys. Normalization procedure includes 1NF, 2NF, 3NF, BCNF, and then the data is normalized.

3.De-normalization

The process of adding redundant data to get rid of complex join, in order to optimize database performance. This is done to speed up database access by moving from higher to lower form of normalization. 

  

                                                                                       or

De-Normalization on the contrary is the process of adding redundant data to speed up complex queries involving multiple table JOINS. One might just go to a lower form of Normalization to achieve De-normalization and better performance. Data is included in one table from another in order to eliminate the second table which reduces the number of JOINS in a query and thus achieves performance.