Database Normalization: Explain 1NF, 2NF, 3NF, BCNF With Examples + PDF: The purpose of normalization is to make the life of users easier. Insertion, Updation and Deletion Anamolies are very frequent if database is not normalized. To understand these anomalies let us take an example of a Student . A relation is said to be in 2NF, if it is already in 1NF and each and every In the 3NF example,Stud_ID is super-key in Student_Detail relation.

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I am an Indian blogger and ranked at number 4th on all time favorite bloggers of India. For instance, exajple first superkey above has just 1 column.

Normalization increases the efficiency of the database. Ruth Hill December 4, Start with the basics and practice the SQL statements.

Also 1nnf that this question is two years old, and already has a highly-upvoted answer that was marked as accepted by the OP.

Consider a toy shop that has three branches in three different locations. If you have any doubt then please comment below. Ted Codd is the one who 3n up with the idea of relational databases – things relying on keys, etc. Doug Mather December 4, 7: The added advantage of getting an organized package of data that helps in a performance boost is also a very notable use of normalization.


Lonnie Bell December 5, Examplw a table that shows the database of a bookstore.

DBMS Normalization: 1NF, 2NF, 3NF and BCNF with Examples

Here is what a sample database could look like:. Dimension and fact tables are used in data warehousing.

Your table is organized as an unordered set of data, and there are no repeating columns. What is the alternative to database normalization?

DBMS Normalization: 1NF, 2NF, 3NF and BCNF with Examples

Summary Database designing is critical to the successful implementation of a database management system that meets the data requirements of an enterprise system.

Any Row must not have 2nc column in which more than one value is saved, instead data is separated in multiple rows as shown below.

Olive Yu December 4, 7: What ecample the difference between normalization and denormalization? Here, the department column is dependent on the professor name column.

What is Normalization? 1NF, 2NF, 3NF & BCNF with Examples

I have written an article in more detail over here. This is not desirable since someone who is updating the database may remember to change the name of the professor, but may forget updating the department value. In such a situation, replicating so much data will increase the storage requirement unnecessarily.


Table 1 contains member information. For example, if you have an employee dimension and the employee belongs to a particular department.

Let us first understand what a superkey means. By splitting the table, the partial functional dependency is removed and atomicity is achieved for both the tables thus realizing 1NF in the process. Suppose there is a company wherein employees work in more than one department. Hackr Team December 4, 7: Before we delve into details of third normal form, let us understand the concept of a functional dependency on a table.

If you are working with or designing an OLTP application where more independent tables are actually given a benefit of storing data in the more optimal way.

You can make another entry and take a composite primary key which will be removed in further normalization. In such a situation, we will have to make edits in 2 places. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Second Normal Form 2NF: