NHibernate efficient Delete using LINQ Where condition

Question

Having a repository for NHibernate with LINQ queries like this

var q = from x in SomeIQueryable<SomeEntity> where x.A1 == a1 && x.B1 == b1 select x;

Is there a solution how to get this WHERE filter and apply it for "one-shot-delete" which seems to be only possible through HQL:

var cmd = string.Format("delete from SomeEntity where x.A1 = '{0}' and x.B1 = {1}", a1, b1);
session.CreateQuery(cmd).ExecuteUpdate();

Answer 1

It is now possible with Nhibernate 5.0:

session.Query<SomeIQueryable>()
            .Where(x => x.A1 == a1 && x.B1 == b1)
            .Delete();

Documentation:

    //
    // Summary:
    //     Delete all entities selected by the specified query. The delete operation is
    //     performed in the database without reading the entities out of it.
    //
    // Parameters:
    //   source:
    //     The query matching the entities to delete.
    //
    // Type parameters:
    //   TSource:
    //     The type of the elements of source.
    //
    // Returns:
    //     The number of deleted entities.
    public static int Delete<TSource>(this IQueryable<TSource> source);

Answer 2

NH LINQ provider and the criteria/queryover API do not support conditional deletes/updates. HQL or raw SQL are the only options unless you are looking into extending NHibernate.

Answer 3

Currently, as of NH 4.0.1, it is not possible. There is, however, an open issue at Jira (NH-3659, https://nhibernate.jira.com/browse/NH-3659 ). There is an hackish solution based on a custom interceptor and SQL replacement described at http://weblogs.asp.net/ricardoperes/strongly-typed-delete-with-nhibernate , but I am working on a clean solution and will eventually submit a pull request.

Answer 4

(from x in NHSession.Query<SomeEntity>()
                  where x.A1 == a1 && x.B1 == b1 
                  select x).ForEach(y => { NHSession.Delete(y) });
        NHSession.Flush();