Comments on: ColdFusion ORM : What is “N+1 Select problem”

By: Rupesh Kumar

Rupesh Kumar — Fri, 26 Mar 2010 11:42:17 +0000

That will be loading the employee object only. So N+1 select problem will not come into play.
It comes into play only if you are loading an object which has *-many relation and the relation has fetch=”select” or it is lazy as I explained above.

By: Henry Ho

Henry Ho — Thu, 25 Mar 2010 09:51:31 +0000

Oops, it should be [department] as the 2nd argument in the code above.

By: Henry Ho

Henry Ho — Thu, 25 Mar 2010 09:50:50 +0000

What if I use HQL:

ormExecuteQuery(”from Employee e where e.department = ?”, [employee])

Is this a N+1 select problem?

By: Rupesh Kumar

Rupesh Kumar — Wed, 16 Sep 2009 13:37:10 +0000

Absolutely !

By: Ben Nadel

Ben Nadel — Wed, 16 Sep 2009 13:22:20 +0000

Rupesh, good explanation. It looks like we are really going to have to know a bit about how Hibernate works to really leverage this integration efficiently. – we can’t just start using it blindly.

By: Rupesh Kumar

Rupesh Kumar — Tue, 15 Sep 2009 07:53:40 +0000

Thanks Hemant for making it more clear

By: Hemant Khandelwal

Hemant Khandelwal — Tue, 15 Sep 2009 04:10:39 +0000

Great posting (again) Rupesh!

The classic N+1 problem in encountered in a simple lazy load scenario in any general application.

1query to get all department objects with PK

SELECT deptID FROM department;

And then query to get all other details of a particular dept

SELECT * FROM department where deptID=?;

The second query is executed as many times (N) as the number of full records you want to fetch. Its when N is high, eager can be a good strategy.