<a href="http://g.adspeed.net/ad.php?do=clk&zid=15220&wd=468&ht=60&pair=as" target="_blank"><img style="border:0px;" src="http://g.adspeed.net/ad.php?do=img&zid=15220&wd=468&ht=60&pair=as" alt="i" width="468" height="60"/></a>
Log in
::
Register
::
Not logged in
Home
Tags
Articles
Editorials
Stairways
Forums
Scripts
Videos
Blogs
QotD
Books
Ask SSC
SQL Jobs
Training
Authors
About us
Contact us
Newsletters
Write for us
<a href="http://g.adspeed.net/ad.php?do=clk&zid=15491&wd=120&ht=300&pair=as" target="_top"><img style="border:0px;" src="http://g.adspeed.net/ad.php?do=img&zid=15491&wd=120&ht=300&pair=as" alt="i" width="120" height="300"/></a>
Recent Posts
Recent Posts
Popular Topics
Popular Topics
Home
Search
Members
Calendar
Who's On
Home
»
Article Discussions
»
Article Discussions by Author
»
Discuss content posted by Ankur
»
Duplicate value in Identity column
29 posts, Page 2 of 3
««
1
2
3
»»
Duplicate value in Identity column
Rate Topic
Display Mode
Topic Options
Author
Message
SanjayAttray
SanjayAttray
Posted Monday, August 16, 2010 7:56 AM
Hall of Fame
Group: General Forum Members
Last Login: Friday, March 15, 2013 2:43 PM
Points: 3,924,
Visits: 1,554
Yes you can insert but should be avoided by having a unique constraint or Pkey on identity column.
Since, it doesn't make much sense, if you want to put duplicate value in identity column then why add identity option to column int. Just leave it as is.
SQL DBA.
Post #969783
Koen Verbeeck
Koen Verbeeck
Posted Monday, August 16, 2010 8:39 AM
SSCrazy Eights
Group: General Forum Members
Last Login: Yesterday @ 6:54 AM
Points: 9,364,
Visits: 6,462
SanjayAttray (8/16/2010)
Since, it doesn't make much sense, if you want to put duplicate value in identity column then why add identity option to column int. Just leave it as is.
I think the idea behind this question is to warn people that just using IDENTITY is not enough. Not everybody knows that duplicate entries can still happen with an IDENTITY, so that is a valuable lesson learned with this question.
How to post forum questions.
Need an answer? No, you need a question.
What’s the deal with Excel & SSIS?
Member of
LinkedIn
. My blog at
LessThanDot
.
MCSA SQL Server 2012 - MCSE Business Intelligence
Post #969830
Rose Bud
Rose Bud
Posted Monday, August 16, 2010 8:39 AM
Ten Centuries
Group: General Forum Members
Last Login: 2 days ago @ 9:42 AM
Points: 1,072,
Visits: 1,026
Interesting. Very surprised to learn you can enter duplicate values when inserting explicit values.
Further surprised to learn that you can get duplicate values by resetting the identity seed, according to this person:
http://beyondrelational.com/blogs/jacob/archive/2009/02/03/sql-server-identity-why-do-i-have-duplicate-identity-values.aspx
Post #969831
SQLRNNR
SQLRNNR
Posted Monday, August 16, 2010 8:50 AM
SSCoach
Group: General Forum Members
Last Login: 2 days ago @ 1:46 PM
Points: 18,732,
Visits: 12,329
Nice question.
Jason
AKA CirqueDeSQLeil
I have given a name to my pain...
MCM SQL Server 2008
SQL RNNR
Posting Performance Based Questions - Gail Shaw
Posting Data Etiquette - Jeff Moden
Hidden RBAR - Jeff Moden
VLFs and the Tran Log - Kimberly Tripp
Post #969849
OCTom
OCTom
Posted Monday, August 16, 2010 2:08 PM
SSCrazy
Group: General Forum Members
Last Login: Yesterday @ 1:42 PM
Points: 2,012,
Visits: 2,839
SanjayAttray (8/16/2010)
Yes you can insert but should be avoided by having a unique constraint or Pkey on identity column.
Since, it doesn't make much sense, if you want to put duplicate value in identity column then why add identity option to column int. Just leave it as is.
Perhaps Microsoft should change it so that a PK or unique constraint must accompany an identity column? Like you say, it doesn't make sense to have it this way and is a potential problem.
Post #970014
Hugo Kornelis
Hugo Kornelis
Posted Monday, August 16, 2010 2:34 PM
SSCertifiable
Group: General Forum Members
Last Login: Today @ 12:12 PM
Points: 5,231,
Visits: 7,021
OCTom (8/16/2010)
Perhaps Microsoft should change it so that a PK or unique constraint must accompany an identity column? Like you say, it doesn't make sense to have it this way and is a potential problem.
I don't see that happening. It could potentially break existing code that relies on identity values not being unique (why? don't ask me - people do the craziest things in SQL Server). And if MS would ban every option that you can use to shoot yourself in the foot, there wouldn't be a lot left...
Hugo Kornelis, SQL Server MVP
Visit my SQL Server blog:
http://sqlblog.com/blogs/hugo_kornelis
Post #970032
VM-723206
VM-723206
Posted Tuesday, August 17, 2010 12:34 AM
SSChasing Mays
Group: General Forum Members
Last Login: Saturday, April 06, 2013 12:20 AM
Points: 649,
Visits: 263
Nice question.
Post #970164
SteveBell
SteveBell
Posted Tuesday, August 17, 2010 4:57 AM
SSC Veteran
Group: General Forum Members
Last Login: Thursday, April 25, 2013 5:59 AM
Points: 209,
Visits: 1,537
Yep,
I got this one wrong also.
However, it begs the question, "why would you want an identity column in the first place if you intend to insert a duplicate value?"
Post #970247
AppSup_dba
AppSup_dba
Posted Tuesday, August 17, 2010 5:09 AM
SSC-Enthusiastic
Group: General Forum Members
Last Login: Yesterday @ 12:14 PM
Points: 125,
Visits: 498
In one scenario we had to copy some data from live DB to test DB. Since the table was having an identity column we were not able to make the data consistent hence we used the above mentioned feature...
Cheers,
Ankur
Post #970253
daniel.noble
daniel.noble
Posted Wednesday, August 18, 2010 3:32 AM
Old Hand
Group: General Forum Members
Last Login: Friday, July 13, 2012 3:12 AM
Points: 373,
Visits: 84
dbowlin (8/16/2010)
Identity insert can be very dangerous. For a long time I couldn't see a use for it. Then I needed it to get 2 tables in 2 different databases into sync after they had fallen out of sync for some unknown reason. It saved me a lot of effort.
I move data from a Live table (with an identity on the PKey) into an Archive table. Just occasionally I need to move a row back into the Live table. Identity insert allows me to move it back with its original ID, thus maintaining references to this row from other tables. So there's one use for it.
Post #970999
« Prev Topic
|
Next Topic »
29 posts, Page 2 of 3
««
1
2
3
»»
Permissions
You
cannot
post new topics.
You
cannot
post topic replies.
You
cannot
post new polls.
You
cannot
post replies to polls.
You
cannot
edit your own topics.
You
cannot
delete your own topics.
You
cannot
edit other topics.
You
cannot
delete other topics.
You
cannot
edit your own posts.
You
cannot
edit other posts.
You
cannot
delete your own posts.
You
cannot
delete other posts.
You
cannot
post events.
You
cannot
edit your own events.
You
cannot
edit other events.
You
cannot
delete your own events.
You
cannot
delete other events.
You
cannot
send private messages.
You
cannot
send emails.
You
may
read topics.
You
cannot
rate topics.
You
cannot
vote within polls.
You
cannot
upload attachments.
You
may
download attachments.
You
cannot
post HTML code.
You
cannot
edit HTML code.
You
cannot
post IFCode.
You
cannot
post JavaScript.
You
cannot
post EmotIcons.
You
cannot
post or upload images.
Copyright © 2002-2013 Simple Talk Publishing. All Rights Reserved.
Privacy Policy.
Terms of Use.
Report Abuse.
