I always ask question about Third Normal Form in interviews I take.
Q. What is Third Normal Form and what is its advantage?
A. Third Normal Form (3NF) is most preferable normal form in RDBMS. Normalization is the process of designing a data model to efficiently store data in a database. The rules of 3NF are mentioned here
- Make a separate table for each set of related attributes, and give each table a primary key.
- If an attribute depends on only part of a multi-valued key, remove it to a separate table
- If attributes do not contribute to a description of the key, remove them to a separate table.
Normalization is very close to concept of object oriented schema’s and it stores one data at only one place by removing all the redundant data. It also helps to draw the schema easier. Normalization comes at the cost of performance.
Reference : Pinal Dave (https://blog.sqlauthority.com) , DataModel.org.
29 Comments. Leave new
Hi…
i need to know my pending jobs for the day…
can u give me some idea on this…
pending means… jobs are scheduled to run for today, but not run for the day.. yet to run… on the day…!
i tried a lot using sysjobschedules table.. but no clue…!
regards,
Raghavendra
i ges its being kept hanging / waiting
SQL Server Agent provides a new stored procedure for enumerating real-time job activity based on the current session.
Performing the query sp_help_jobactivity reveals a list of all active SQL Server Agent jobs.
This new stored procedure for enumerating real-time job activity obtains some data from the sysjobactivity table in msdb.
The sysjobactivity table is where SQL Server Agent stores job status information for the current session and all previous sessions of SQL Server Agent.
If the SQL Server Agent Service fails unexpectedly, users can determine which SQL Server Agent jobs were in the middle of being executed by looking that the sysjobactivity table for the previous session.
Hi Pinal,
Very well explained…
Thanks and keep it up.
-Surendra
Hi Pinal,
Can you please explain 3rd NF with example?
Thanks & Regards
Pravin Patel.
hi
would u mind please explain 3rd NF with example?
hi sir,
i m alws confus about normalization………
plz explain with simple example
Kindly Define 3rd Normal Form with two Example
thanks
sakendra kumar
What are the different types of backup avaible in SQL SErver
how many instance use in sql server 2000,2005,2008
I have 98 lac row in a table. To fetch a query it takes too much time. give me some idea to improve the performance.
here we have already used non-clustered index on required column and also repairing time to time.
thanks
to sakendra kumar.
what u can do is
1.limit the no of columns in ur select query
2.check the fragmentation of indexes on that table
and accordingly rebuild or reorganize.
3.use recommendations from db tuning advisor.
4. check he execution plan and find out to get ur results
how many rows it is scanning
Hi Pinal,
Can you explain me the normalization process through an example?(All the normal forms 1NF, 2NF, 3NF, BCNF, 4NF, 5NF).
i m beginner to sql server 2005
so teach me job schedules concept one by one
Please help me
How can i know in which NF the tabe is?
For example I have a table created like this:
CREATE TABLE customers
(
cCustomer ID char(4) not null constraint pkCustomerID primary key,
CCustName char(20) not null,
vCustName varchar(20) not null,
CAddress char(40) not null,
CCity char(20) null,
CState char(20) null,
CPhone char(10) null,
)
Pinal Sir,
i’m new to ur blog sir. Recently found u sir. It’s Very useful and helpful to us sir.
And i’m a fresher for Sql.
I need simple examples how to use Stored procedure and Trigger.
Kindly Reply me sir..
Read about them in SQL Server help file. It has explanations as well as examples
Hi,
Can you please explain all normal forms with eaxmple?
I also want examples.
Pinal please give examples of each type of normalization.
Thanks in advance.
Hi Pinal,
You have written very nice article.
Thanks for sharing with us.
Good One !
please tell me
is there any code review tool for sql?
please tell me
is there any code review tool for sql?
hi
I am not getting any use of BCNF. can u give me one example where BCNF is imlemented.
thanks
vikas