CODEWITHSUNDEEP
nhibernatelinq-to-nhibernate
Chris
Chris

Reputation: 1251

nhibernate linq: projection to DTO and columns

I've recently upgraded my Linq provider to the new AST one. (NH3 on NuGet)

With the previous provider I was using linq to do "inline projections to my DTO" e.g. 

from o in Session.Query<MyObject>() 
select new MyObjectDTO { 
Name = o.Name, 
SubName = o.OtherObject.Name, 
Sub2NAme = o.OtherObject2.Name 
}

and this would generate a 

SELECT o.Name, sn1.Name, sn2.Name FROM ..... 
JOIN.... JOIN....

statement.

Once I upgraded my provider I found a lot of select statements being fired off. (My projected object is more complex than above). I have come accross Fetch/FetchMany, which might help with the number of queries, but as far as I can tell it means the full object will come back for each flattened field I require.

Is there a way I can get the smallest possible number of columns required for the projection to be selected, rather than loading the full object graph to the project with?

Thanks, Chris

Upvotes: 3

Views: 1702

Answers (1)

Diego Mijelshon
Diego Mijelshon

Reputation: 52725

It must be something with your usage of the result (like iterating many times the IQueryable), something odd with the mappings, or some complexity that was removed from the example.

I just tried that exact query, and only one SQL statement was generated.

Upvotes: 1

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