[nhibernate-issues] [NHJIRA] Commented: (NH-2703) Using a "with" restriction in outer joins result in wrong SQL

[Roy J. (JIRA) <nh...@gm...>]

    [ http://216.121.112.228/browse/NH-2703?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=21091#action_21091 ] 

Roy Jacobs commented on NH-2703:
--------------------------------

I have attached a patch that solves the issue by sorting the associations with a 'with' clause based on dependencies. I took the topology sorting code from a blog (as indicated in the code).

The analysis of which aliases are used in the 'with' clause uses a regex to figure out the names of the aliases. I realize there must be a cleaner way to do this, but for the life of me I couldn't extract the aliases without it becoming a huge complicated mess (e.g. parsing PropertyExpressions and Subcriteria and so on).

As it is, this solution seems to work and all unit tests pass.

> Using a "with" restriction in outer joins result in wrong SQL
> -------------------------------------------------------------
>
>                 Key: NH-2703
>                 URL: http://216.121.112.228/browse/NH-2703
>             Project:  NHibernate
>          Issue Type: Bug
>          Components: QueryOver
>    Affects Versions: 3.2.0Beta1
>            Reporter: Roy Jacobs
>            Priority: Major
>         Attachments: JoinTest.zip, nh2703-fix.patch
>
>
> I have a Parent class that has two types of children: "Child" in a list called "Children" and "Other" in a list called "OtherChildren".
> If I do a QueryOver on Parent, and outer join both Child and Other tables then everything works.
> If I add a "With" on the "Child" join, linking it to "Other" (e.g. child.MyProp == other.OtherProp) then the SQL that is generated does not work in SQL Server 2008:
> SELECT child2_.MyProp as y0_
> FROM Parent this_
> left outer join Child child2_ on this_.Id=child2_.parent_id and ( child2_.MyProp = other1_.OtherProp )
> left outer join Other other1_ on this_.Id=other1_.parent_id
> The error message is:
> System.Data.SqlClient.SqlException : The multi-part identifier "other1_.OtherProp" could not be bound.
> This is because SQL Server expects "other1_" to be joined *BEFORE* "child2_". If I manually change the join order around in the SQL, it works.
> Reshuffling the order in which I perform the joins in C# does not help, the emitted SQL is always incorrect.
> I have attached a failing test that can be added to NHibernate.Test which demonstrates this problem.

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