That is what this article is all about.

http://www.primordialcode.com/blog/post/nhibernate-customize-linq-provider-user-defined-sql-functions

or this

http://fabiomaulo.blogspot.com/2010/07/nhibernate-linq-provider-extension.html

/G

2011/8/31 mysterd429 <[email protected]>

> Gunnar,
>
> Thanks for your help so far.  I originally had a UDF, so I've
> converted back to the UDF.  I've got an extension method for
> ResultObject called GetSearchRank, which takes the same parameters as
> the UDF in addition the "this" parameter and returns -1 (temporarily
> for testing).  I've created a dialect that is a subclass of
> MsSql2008Dialect, an HQL generator that is a subclass of
> BaseHqlGeneratorForMethod, and an HQL generators registry that is a
> subclass of another HQL generators registry common to all of our
> projects (all it does it add the "trim" function for strings.)
>
> When I try to run the code, the generator registry is getting built,
> and execution goes to the BuildHql gets called (I've not yet
> implemented it) when I do Session.Query<ResultObject>().OrderBy(ro =>
> ro.GetSearchRank("foo", "bar")), but when I do
> Session.Query<ResultObject>().Select(ro => ro.GetSearchRank("foo",
> "bar")), I just get a queryable full of -1.
>
> How can I get NHibernate to translate the method call to SQL instead
> of executing it on the .NET side?
>
> Thanks!
>
>    Don
>
> On Aug 30, 7:54 pm, Gunnar Liljas <[email protected]> wrote:
> > Since you're inlining this in a SELECT, you should not use your SP.
> Either
> > use FREETEXTTABLE directly or create a UDF.
> >
> > The steps are:
> >
> > 1. Customize the SQL dialect and configure NHibernate to use it
> > 2. Register the functions in the Linq provider
> > 3. Something like what you described.
> >
> > /G
> >
> > 2011/8/30 mysterd429 <[email protected]>
> >
> >
> >
> >
> >
> >
> >
> > > Hi, Gunnar,
> >
> > > Okay, that will work, I think.  I would use my existing stored
> > > procedure rather than FREETEXTTABLE.  Would these be the steps:
> >
> > > 1. Customize the LINQ provider using something like
> > > RegisterFunction("GetRank", /* SQLFunctionTemplate or
> > > StandardSQLFunction, not sure, that calls DO_SEARCH using T-SQL */).
> > > 2. Do something like this:
> >
> > > String field1, field2, field3;
> > > // assign field1, field2, field3
> > > IQueryable<SearchResult> queryable =
> > > Session.Query<ResultObject>().Select(ro => new SearchResult
> > > { ResultObject = ro, Rank = GetRank(ro, field1, field2,
> > > field3) }).Where(ro => GetRank(ro, field1, field, field3) ?? 0 > 0);
> > > if(myUtilityInstance != null) queryable =
> > > myUtilityInstance.Paginate(queryable);
> > > results = queryable.ToList();
> >
> > > Does that seem about right?  Thanks so much for your help!
> >
> > > Regards,
> >
> > >    Don
> >
> > > On Aug 30, 3:40 pm, Gunnar Liljas <[email protected]> wrote:
> > > > Hi,
> >
> > > > While there may be ways to get the result set of a stored procedure
> into
> > > an
> > > > NhQueryable, it doesn't make much sense, since any extra Linq
> predicates
> > > you
> > > > apply will then by run on the full result set (when paging etc.), and
> if
> > > you
> > > > do that, you might just as well apply it after the query, with in
> memory
> > > > operations.
> >
> > > > I still think that a custom SQL function is feasible. You will have
> to
> > > > reshape it into a scalar value...
> >
> > > > SELECT ...., (SELECT [RANK] FROM
> FREETEXTTABLE(tableref,columnref,value)
> > > > WHERE [KEY]=tableref.Id) as [RANK] FROM ...
> >
> > > > Maybe not easy, but doable.
> >
> > > > /G
> >
> > > > 2011/8/30 mysterd429 <[email protected]>
> >
> > > > > Thanks for the reply, Gunnar.  Unfortunately, I don't see how I can
> > > > > use these links.  I'm trying to use FREETEXTTABLE, which provides a
> > > > > result set with the search results, not FREETEXT, which is scalar.
>  I
> > > > > need to know not only that a row matches, but what its relative
> rank
> > > > > is in the result set.  From the MSDN documentation, FREETEXTTABLE
> > > > > "[r]eturns a table of zero, one, or more rows for those columns
> > > > > containing character-based data types for values that match....
> > > > > FREETEXTTABLE can only be referenced in the FROM clause of a SELECT
> > > > > statement like a regular table name."  The stored procedure I have
> > > > > essentially wraps FREETEXTTABLE.
> >
> > > > > Is there any way to get the result set of a stored procedure into
> an
> > > > > NhQueryable?
> >
> > > > > Thanks!
> >
> > > > > On Aug 30, 11:55 am, Gunnar Liljas <[email protected]>
> wrote:
> >
> > >http://www.primordialcode.com/blog/post/nhibernate-customize-linq-pro.
> ..
> >
> > > > > > and
> >
> > >http://darioquintana.com.ar/blogging/2009/03/13/registering-freetext-.
> ..
> >
> > > > > > 2011/8/30 mysterd429 <[email protected]>
> >
> > > > > > > Hi all,
> >
> > > > > > > I've got an existing database that uses FREETEXTTABLE in a
> stored
> > > > > > > procedure.  I've been using the NHibernate LINQ provider (since
> > > we're
> > > > > > > switching from LINQ to SQL to NHibernate), and I'd like to know
> if
> > > > > > > there's a way to use FREETEXTTABLE using the LINQ provider.
>  The
> > > > > > > stored procedure takes a few parameters and selects the desired
> > > result
> > > > > > > set (KEY and RANK columns).  I have a class for these search
> result
> > > > > > > rows.
> >
> > > > > > > Currently, I can use the stored procedure using a named SQL
> query
> > > and
> > > > > > > get back attached entities:
> >
> > > > > > > IQuery query = Session.GetNamedQuery("DoSearch");
> > > > > > > query.SetParameter("searchTerm", searchTerm);
> > > > > > > IList<SearchResult> results = query.List<SearchResult>();
> > > > > > > // results[0].ResultObject is the first underlying object.
> >
> > > > > > > We have a few utility methods that use LINQ for some processing
> > > > > > > (sorting, pagination, etc) that I'd like to reuse with this
> stored
> > > > > > > procedure.
> >
> > > > > > > Ideally, I'd like to do something like:
> >
> > > > > > > var doSearch =
> > > Session.GetQueryableObjectFromNamedQuery("DoSearch");
> > > > > > > doSearch.SetParameter("serachTerm", searchTerm);
> > > > > > > IQueryable<SearchResult> resultsQueryable =
> doSearch.AsQueryable();
> > > > > > > IList<SearchResult> results =
> > > > > > > myUtilityInstance.SortAndPaginate(resultsQueryable);
> >
> > > > > > > Any ideas?  Thanks!
> >
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