Ayende @ Rahien

Jim commented on NHibernate trickery: what happened to my associations?

Mon, 02 Nov 2009 22:27:21 GMT

What the conclusion?

David Kemp commented on NHibernate trickery: what happened to my associations?

Mon, 02 Nov 2009 10:45:26 GMT

@Lothan - that seems to be the problem. NHibernate seems to want a collection called [TrickyBug.User.AllowedPaths#Ayende], but it actually loads a collection called [TrickyBug.User.AllowedPaths#ayende] (based ion the database), so you get a log something like: collection fully initialized: [TrickyBug.User.AllowedPaths#Ayende] collection fully initialized: [TrickyBug.User.AllowedPaths#ayende] 2 collections initialized for role: TrickyBug.User.AllowedPaths Note that it says there were 2 collections loaded! Normally only one would be found for an association like this. @ayende - very subtle bug. Well highlighted.

José Romaniello commented on NHibernate trickery: what happened to my associations?

Mon, 02 Nov 2009 10:44:23 GMT

An array is not a valid Set. The user will not be saved. I used to have my collections with "private set".

Ayende Rahien commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 21:57:30 GMT

Benny, [nhprof.com/.../Alert](http://nhprof.com/Learn/Alert?name=DoNotUseImplicitTransactions)

Scott Muc commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 19:00:38 GMT

Sorry to bring up something off topic but why do you have the line tx.Commit(); line in the 2nd using block? It is just for consistency? I thought the idea of a commit is only when performing updates and inserts.

Jason Y commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 17:56:14 GMT

Interesting. One of our apps that interacts with legacy databases had a problem of this exact sort. Our quick workaround was to normalize the case across tables. I'm looking forward to details on what's happening here!

Lothan commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 16:57:04 GMT

I would expect the output to be: Ayende \t/meetings \t/users since this seems to be the intent of the fetch. However, NHibernate blindly performs a case-sensitive comparison on the join even though the database comparison is case-insensitive. More to the point, I question whether this is really a bug in the code or a bug in NHibernate. Even though you requested to load Ayende, the database actually returned ayende and NHIbernate is ignoring that. Shouldn't the data in the database be the key instead of the data in the query? Even so, you'll still run into problems in cases in which the collections contain mixed case (e.g. ayende in some records and Ayende in others). We had to work around this issue by creating our own case-insensitive comparer.

Yitzchok commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 16:00:15 GMT

The problem (I think) is with case-sensitivity What seems to happen is that SqlServer returns the expected result but for some reason Hibernate checks for case-sensitivity when filtering the set (collection). What is I think the most interesting part (and probably the bug you are talking about) is that NHibernate returns a User object with the Username "Ayende" (capital A) which isn't in the Database (it should be "ayende"). It looks like NHibernate uses the Get value for the Key (not the value from the Database) which isn't a problem in most cases (int or Guid).

Benny Thomas commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 14:16:33 GMT

Where is the article/blog why you should use a transaction with commit on a read operation? I think I have to read me up on that!

Markus Zywitza commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 12:21:15 GMT

That should have read: Is it possible to map to ICollection without an IUserCollectionType?

Markus Zywitza commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 12:19:05 GMT

Is it possible to map

Will commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 12:15:58 GMT

It is the capitalisation of the username: "ayende" in the Save and "Ayende" (capital A) in the Get. This is fine for the Get but confuses the loading of the AllowedPaths. I am guessing that this is because Get issues a SQL query and SQL is not case sensitive and that either the AllowedPaths uses a case sensitive SQL query (which I doubt) or the matching is done in code with a case sensitive comparer.

Tapio Kulmala commented on NHibernate trickery: what happened to my associations?

Sun, 01 Nov 2009 12:00:55 GMT

Hi! "ayende" vs "Ayende"? Non case-sensitive DB? Tapio