nhibernate - restriction based on an expression

Question

I am using nHibernate Criteria and I'm stuck on something that seems like it should be really simple. in SQL it would be:

WHERE startPos + length > 17

(startPos and length are two columns on the table). Can anyone help me achieve this with nHibernate

I think it's not possible with criteria, unless you use an SQL expression. Use HQL or Linq instead. — Stefan Steinegger, Dec 14 '13 at 11:30

score 0 · Accepted Answer · answered Dec 14 '13 at 12:04

0

This is the way how to do that with Criteria in NHibernate:

var criteria = session.CreateCriteria<MyEntity>(); // C# MyEntity

criteria.Add(
  // add restriction
  Restrictions.Gt(
    // left part as a projection
    Projections.SqlProjection(
        "(startPos + length) as myAlias"
        , new[] {"myAlias"}
        , new IType[] {NHibernateUtil.Boolean} )
    // right part 
    , 17
    ));

answered Dec 14 '13 at 12:04

Radim Köhler

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Thanks that works great! - I haven't used projections before so I think I'll need a bit of time with the manual now to figure out how it actually works though :) – Andy Dec 15 '13 at 08:29
NHibernate is amazing tool. It can do really a lot for us. So do not hesitate and do dive in even more ;) Good luck with NHibernate – Radim Köhler Dec 15 '13 at 08:30

nhibernate - restriction based on an expression

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