13 Aug 06:58
Linq project added to core
From: Will Shaver <will.shaver <at> gmail.com>
Subject: Linq project added to core
Newsgroups: gmane.comp.windows.dotnet.nhibernate.devel
Date: 2008-08-13 05:02:12 GMT
Subject: Linq project added to core
Newsgroups: gmane.comp.windows.dotnet.nhibernate.devel
Date: 2008-08-13 05:02:12 GMT
It looks like Chad Lee added the NHibernate.Linq project and NHibernate.Linq.Test projects to the vs2008 solution. Cool.
I spent a few hours tonight going over Linq to NH project and Reflecting over Linq to SQL. (What a mess that is.)
If none of you have read this article here:
It seems like a good place to start learning linq.
So the current implementation of linq to NH (contrib) appears to do this: (please correct if I'm wrong)
NHibernateQueryProvider->Execute(Expression)
//clean expression, translate nodes to NHibernateExpression type where needed
//visit all expression creating and appending to an ICriteria for each part of the query.
//execute the ICriteria
Easy enough. We're doing something a bit more complicated this time around...
NHibernateQueryProvider-> Execute(Expression expression)
//clean expression tree, translate nodes to NHibernateExpression type where needed. ***
//this translation is done by consulting the using the SessionFactory for metadata on each item in the expression
option1:
//Translate NHExpression to SqlString here?
//Pass SqlString to Dialect for translation (Things like factory.Dialect.GetLimitString(sql string))
option2:
//Pass NHExpression to the Dialect for limit strings ect,
public virtual SqlString GetLimitString(SqlString querySqlString, bool hasOffset)
becomes
public virtual NHibernateExpression ProcessLimitString(NHibernateExpression expression)
Which our translator calls to add in that dialect's specific limit string and other quirks.
//Then take the SqlString and process into entities and return as done in Loader... Or put processing of the NHibernateExpression in Loader?
Let me know what you folks think.
***Linq To SQL appears to translate to a different tree type that is not inherited from Expression, but contains an Expression property. Perhaps there is a good reason for this? Review SqlNode in System.Data.Linq.SqlClient via Reflector. Ironically they also have a direct copy and paste of the internal marked ExpressionVisitor class in here as well...
-Will
------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________ Nhibernate-development mailing list Nhibernate-development <at> lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nhibernate-development
RSS Feed