Skip to main content

Delete Vs Truncate Statement

• Delete table is a logged operation, so the deletion of each row gets logged in the transaction log, which makes it slow.

• Truncate table also deletes all the rows in a table, but it won’t log the deletion of each row, instead it logs the de-allocation of the data pages of the table, which makes it faster. Truncate table can be rolled back if it happens within a Transaction.

• Truncate table is functionally identical to delete statement with no “where clause” both remove all rows in the table. But truncate table is faster and uses fewer system and transaction log resources than delete.

• Truncate table removes all rows from a table, but the table structure and its columns, constraints, indexes etc., remains as it is.

• In truncate table the counter used by an identity column for new rows is reset to the seed for the column.

• If you want to retain the identity counter, use delete statement instead.

• If you want to remove table definition and its data, use the drop table statement.

• You cannot use truncate table on a table referenced by a foreign key constraint; instead, use delete statement without a where clause. Because truncate table is not logged, it cannot activate a trigger.

• Truncate table may not be used on tables participating in an indexed view.

Comments

Anonymous said…
This is a nice technical article.

Thanks!!
Vignesh
dangiankit said…
Thanks, a good one.
Anonymous said…
very gud one!quite informative!
Anonymous said…
very informative!Thanks!
Anonymous said…
Nice list, however it is misleading in that TRUNCATE TABLE can be rolled back within a transaction. TRUNCATE TABLE however cannot be rolled back after a transaction is committed by using the transaction log.
Vadivel said…
Hello Anonymous :) Truncate information can also be rolledback if it happens within a transaction.

Check out my other blog post on this topic here - http://vadivel.blogspot.com/2006/12/rolling-back-truncate-operation.html
Chidamparam said…
My requirement is: create a temp table, insert data, take a dump, move it to another DB, then truncate the table and then Insert the data and then the above cycle continues periodically.
Finding performance issue due to long duration of truncate.

Can I use drop table instead of truncate ?
any other alternate approach to meet the above requirement
sourabh deepraj said…
Hi Vadivel,
i have heard that delete can be rolled back.
If i want to roll back delete statement,How can i do that without keeping in transaction block?

that is without using--

begin transaction
delete from table1
rollback transaction

Popular posts from this blog

My Wedding Anniversary :)

Six years back on the same day I married Sai Lakshmi (12-July-2000). I know Sai for almost 13 years now :) I fell in love with her during my 12th standard. I know @ 17 yrs any person wouldn't be matured enough to make a big decision like this. But thank God my choice was perfect :) Even now, very often we used to think about the past and laugh at our behaviors/actions then. My love story would be really interesting (at least for me and Sai :)) and I am sure none of you guys would be interested in reading about it so lemme not get into it in-depth. But one thing which I want to share is "Without Sai, I wouldn't have entered into the IT field at all". She was instrumental in convincing me to study my Master's degree in Computer Application. That's the move that changed my career. Till my schooling, my dream was to either become a "big" sportsman (Cricket and Badminton were my favorites at that time.) or an Aeronautics engineer. Unfortunately, my l...

What should one look @ while buying a land in chennai?

Offlate people have started thinking about investing their money in lands. I too think that to be a wise decision only! As most of us know buying a land in chennai (for that matter any where in the world) isn't an easy affair. I was just wondering what all one needs to look at before deciding to purchase a land. I thought I would put down what ever I know about this subject here. [Guys pls free to correct me if I my understanding is wrong somewhere. That way, it would help me understand as well as others who might read this in future]. Here we go ... 1. One should not buy farm lands if they want to build a residential house sometime later there. Because to my knowledge its illegal to build residential houses on lands meant for irrigation. 2. Encumberance Certificate -- This is what is shortly refered as "EC". One needs to get an EC from local sub registrar office (i guess we need pay a small amount for this). From this we / our lawyers :) can find out whether the guy who ...

Tips for attracting more comments …

After a long silence I am blogging regularly for almost past 2 months now. Btw, I use “ eXtreme Tracking ” to track the traffic into my blog. When I check the summary of those results I am really happy to know that in the past 231 days I have got 6711 unique visitors . Out of which last month I have attracted 1362 unique visitors and this month (as of today 7 PM) there are 1733 unique visitors. I think this to be a good count. I want to reiterate that out of 231 days I have seriously blogged for couple of months only. Ok with that information, I want to talk about the problem in hand. Only recently I started thinking “dude, you are getting decent amount of readers on a daily basis. But then you aren’t getting much feedback from them. What’s the problem?” Just because I am not getting decent amount of feedbacks does it mean my blog isn’t informative? I really don’t know but I know that, normally people are reluctant to post their views as comments on site for various reasons. In my vie...