2012-09-06
2,737 reads
T-SQL
The Seven Sins against T-SQL Performance
There are seven common antipatterns in T-SQL coding that make code perform badly, and three good habits which will generally ensure that your code runs fast. If you learn nothing else from this list of great advice from Grant, just keep in mind that you should 'write for the optimizer'.
2012-08-29
7,758 reads
2012-08-28
2,590 reads
2012-08-27
2,748 reads
2012-08-23
2,985 reads
2012-08-21
2,809 reads
Hierarchies in SQL, Part II, the Sequel
In a followup to his first article on Hierarchies, Gus Gwynn takes a look at the performance of a few different methods of querying a hierarchy. Learn how the HierarchyID stacks up.
2012-08-21
7,988 reads
2012-08-20
3,523 reads
2012-08-17
3,540 reads
2012-08-16
3,010 reads
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Don't Forget About Financial Skills
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Building a Simple SQL/AI Environment
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Checking Identities
Comments posted to this topic are about the item Checking Identities
Question of the Day
Checking Identities
The DBCC CHECKIDENT command is used when working with identity values. I have a table with 10 rows in it that looks like this:
TravelLogID CityID StartDate EndDate 1 1 2025-01-11 2025-01-16 2 2 2025-01-11 2025-01-16 3 3 2025-01-11 2025-01-16 4 4 2025-01-11 2025-01-16 5 5 2025-01-11 2025-01-16 6 6 2025-01-11 2025-01-16 7 7 2025-01-11 2025-01-16 8 8 2025-01-11 2025-01-16 9 9 2025-01-11 2025-01-16 10 10 2025-01-11 2025-01-16The docs for DBCC CHECKIDENT say this if I run with only the table parameter: "If the current identity value for a table is less than the maximum identity value stored in the identity column, it is reset using the maximum value in the identity column. " I run this code:
DELETE dbo.TravelLog WHERE TravelLogID >= 9
GO
DBCC CHECKIDENT(TravelLog, RESEED)
GO
INSERT dbo.TravelLog
(
CityID,
StartDate,
EndDate
)
VALUES
(4, '2025-09-14', '2025-09-17')
GO
What is the identity value for the new row inserted by the insert statement above? See possible answers