Comments on: On Sequences with MongoDB and NoRM

By: jzablocki

jzablocki — Thu, 30 Dec 2010 21:10:11 +0000

99.9% of the time I’m building apps with Spring.NET, so all of my repositories are treated as singletons. But I agree with your broader suggestion.

As for the $inc or findAndModify. While those achieve similar results, they don’t satisfy the same use cases as a sequence. For example, with a sequence, I can have a master ID collection that I can use to reserve IDs for data deployment across multiple environments.

By: Froyke

Froyke — Thu, 30 Dec 2010 20:43:07 +0000

This solution is problematic for 2 reasons:
1. The sequence repository should be implemented (or used) as Singelton. if not, the lock should be static.
2. This solution cannot be implemented in a multi-servers scenarios.

A better implementation of this concept would be using native atomic MongoDB structs such as $inc or findAndModify

By: jzablocki

jzablocki — Fri, 05 Nov 2010 16:10:20 +0000

The HiLo shorter IDs are useful, but I still like having the ObjectID for its timestamp. Might save an extra index in some cases…

By: Eduardo Campañó

Eduardo Campañó — Fri, 29 Oct 2010 16:14:40 +0000

I’ve just corrected the NoRM wiki because it says that using int you’ll get the key generated but the correct way is using int?. I had the same problem using GUIDs.

By: Gabriel Florit

Gabriel Florit — Sun, 05 Sep 2010 07:11:53 +0000

If you set the id property as int?, MongoDB assigns the key using HiLo, which results in shorter ids:

public int? Id { get; private set; }