normalization

Question

In an interview i was asked this question by an interviewer and i can't answer this question, plz reply me the answer.

The question is,

I had a table containg some rows and i divided it into 2 or more tables using normalization. Now which gives better performance a single table or a normalization tables. I said normalization tables give better performance. He asked me to give an example but i couldnt.

Plz give me an example with clear explanation.

Thanku.

Pradeep Shet · Answer

Hi Actual speaking normalization doesn't give better performance it actually helps us to avoid redundant data and store data in a organized way. Because of which managing or manipulating will be easier. But this costs to it performance so we need to denormalize it just if you want to fetch data. For reference http://www.c-sharpcorner.com/UploadFile/cda5ba/understanding-normalization-in-database-design/

Jignesh Trivedi · Answer

Hi Normalization: Normalizing data means eliminating redundant information from a table and organizing the data so that future changes to the table are easier Normalization may improve the query performance in some case. As definition of normalization more column table may split into multiple table (within logical grouping). when you want to fetch all the data you have required joins so it may degrade the performance of query. hope this will help you.

Serge · Answer

Hi Since it was an interviewer the answer should a been simple. The non normalized table has a higher performance since it has all the information in one line.

Pankaj Kumar Choudhary · Answer

Definition of Normalization Given by All other Authors is correct. Normalization is used to increase performance of database but some time more normalization can Generate some Opposite result that can reduce the performance of database . Then Denormalization precess is performed..

Michal Habalcik · Answer

hi WikiPedia has a great explanation on this topis. In simple words: Database normalization is the process of organizing the attributes and tables of a relational database to minimize data redundancy. More info: Wikipedia

Afzaal Ahmad Zeeshan · Answer

Normalization is usually a method to convert a database table into more efficient and well-organized form of sub-tables. Most usuall problems that occur in database are redundancy problem data inconsistency and similar integrity problems. You use database normalization to convert the table into a more efficient form. To remove these problems. In the first second and third stage you remove the grouping of data (redundancy) dependancies over non-key attributes or transitive dependancies. This way the new tables (sub-tables) formed are free from these errors. Thus they're better in performance. They also don't have the anomalies for insertion updation and/or deletion.