[nhibernate-issues] [NHJIRA] Created: (NH-2784) NHibernate does extra select on each missing relations, even using an eager fetching.

[Peter K. (JIRA) <nh...@gm...>]

NHibernate does extra select on each missing relations, even using an eager fetching.
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                 Key: NH-2784
                 URL: http://216.121.112.228/browse/NH-2784
             Project:  NHibernate
          Issue Type: Bug
          Components: Core
    Affects Versions: 3.1.0
            Reporter: Peter Kiers


When I do an eager join on a relation table, whenever the relation is missing it will generate an additional query for each missing relation.

Table layout / data:
TableName: Order
+----+-----------+--------+
| Id | OrderName | UserId |
+----+-----------+--------+
| 1  | OrderA    | 1      |
| 2  | OrderB    | 2      |
| 3  | OrderC    | 3      |  
+-------------------------+  

TableName: User
+----+-----------+
| Id | UserName  |
+----+-----------+
| 1  | User1     |
| 2  | User2     |
+----------------+

var orders = session.CreateCriteria<Order>().SetFetchMode("User", 
FetchMode.Eager).List<Order>(); 

Console output:
NHibernate: SELECT this_.Id as Id0_1_, this_.OrderName as OrderName0_1_, this_.User_id as User3_0_1_, user2_.Id as Id1_0_, user2_.UserName as UserName1_0_ FROM[Order] this_ left outer join [User] user2_ on this_.User_id=user2_.Id
NHibernate: SELECT user0_.Id as Id1_0_, user0_.UserName as UserName1_0_ FROM [User] user0_ WHERE user0_.Id=@p0;@p0 = 3 [Type: Int32 (0)]

As you can see it tries to get UserID 3 (which doesn't exists) but it should already know it isn't there as I did a eager fetchmode on that table.

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