Nhibernate and like statement on XML field - nhibernate

Question

I have a wrapped fluent nhibernate framework that I'm reusing and have no control over the actual mapping.
In my entity object I have a property mapped as string to an XML column in sql.
Hence when I run a query like:
var myResult = (from myTable in DataManager.Session.Query<Table>()
where myTable.thatXmlFieldWhichIsMappedAsString.Contains(AnXmlSnippet))
select myTable).FirstOrDefault();
It is trying to use the LIKE operator in SQL which is invalid on that column type.
How can I get around this without having to select all the rows and converting to List first?

Answer 1

In case, that we do not need .Query() (LINQ), and we can use Criteria query or QueryOver, we can use conversion:
// the projection of the column with xml
// casted to nvarchar
var projection = Projections
.Cast(NHibernateUtil.StringClob
, Projections.Property("thatXmlFieldWhichIsMappedAsString"));
// criteria filtering with LIKE
var criteria = Restrictions.Like(projection, "searched xml");
// query and result
var query = session.QueryOver<MyEntity>()
.Where(criteria)
;
var result = query
.SingleOrDefault<MyEntity>()
;
From my experience this could lead to conversion into small nvarchar(255) - sql server... Then we can do it like this:
var projection = Projections
.SqlProjection("CAST(thatXmlFieldWhichIsMappedAsString as nvarchar(max)) AS str"
, new string[]{}
, new NHibernate.Type.IType[]{}
);