Your first (native) code doesn't execute queries. Do you miss a code line
in your example or it's working because it does nothing?
On Monday, April 20, 2015 at 5:31:40 PM UTC+3, Petr Waclawek wrote:
>
> I'm trying to optimize the performance of database operations for a
> typical parent-child entities scenario. In my case I would like to delete
> all children and update the parent's record timestamp in one call to
> database. I'm only able to do it using Native SQL (which I would like to
> avoid):
>
> private static void ClearUsingNativeSql(ISession session,
> ParentItem p)
> {
> var q1 =
> session.CreateSQLQuery("delete from Child_Items where
> Parent_id = :parentId1")
> .SetParameter("parentId1", p.Id)
> .FutureValue<int>();
>
>
> var q2 =
> session.CreateSQLQuery("update Parent_Items set timestamp
> = :timestamp where parent_item_Id = :parentId2")
> .SetParameter("parentId2", p.Id)
> .SetParameter("timestamp", DateTime.Now)
> .FutureValue<int>();
>
>
> _log.Info("Runing native SQL queries");
> var dummy = q2.Value;
> }
>
>
> When I'm trying to use HQL with MultiQuery / Future queries, I'm getting
> the following null reference exception:
>
> System.NullReferenceException: Object reference not set to an instance of
> an object.
> at NHibernate.Impl.MultiQueryImpl.AggregateQueriesInformation()
> at NHibernate.Impl.MultiQueryImpl.get_Parameters()
> at NHibernate.Impl.MultiQueryImpl.CreateCombinedQueryParameters()
> at NHibernate.Impl.MultiQueryImpl.List()
> at NHTest1.Program.ClearUsingMultiQuery(ISession session, ParentItem p)
> in c:\Projects\Test\NHTest\NHTest1\Program.cs:line 238
> at NHTest1.Program.<>c__DisplayClassf.<BatchHqlTest>b__b(ISession
> session) in c:\Projects\Test\NHTest\NHTest1\Program.cs:line 165
> at NHTest1.Program.RunInTransaction(Action`1 action, ISession session)
> in c:\Projects\Test\NHTest\NHTest1\Program.cs:line 332
> at NHTest1.Program.BatchHqlTest(String[] args) in
> c:\Projects\Test\NHTest\NHTest1\Program.cs:line 152
>
> Here is the code, I'm using:
>
> private static void ClearUsingMultiQuery(ISession session,
> ParentItem p)
> {
> var q1 = session
> .CreateQuery("delete from ChildItem c where c.Parent =
> :parentId1")
> .SetParameter("parentId1", p.Id);
>
>
> var q2 = session
> .CreateQuery("update ParentItem p set p.Timestamp =
> :timestamp where p.Id = :parentId2")
> .SetParameter("timestamp", DateTime.Now)
> .SetParameter("parentId2", p.Id);
>
>
> var q = session.CreateMultiQuery().Add(q1).Add(q2);
>
>
> _log.Info("Runing multiplqueriy");
> var dummy = q.List();
> }
>
>
>
> or
>
> private static void ClearUsingFuture(ISession session, ParentItem
> p)
> {
> var q1 = session
> .CreateQuery("delete from ChildItem c where c.Parent =
> :parentId1")
> .SetParameter("parentId1", p.Id)
> .FutureValue<int>();
>
>
> var q2 = session.
> CreateQuery("update ParentItem p set p.Timestamp =
> :timestamp where p.Id = :parentId2")
> .SetParameter("parentId2", p.Id)
> .SetParameter("timestamp", DateTime.Now)
> .FutureValue<int>();
>
>
> _log.Info("Runing multiquery");
> var dummy = q2.Value;
> }
>
>
> Digging into NH source code I found that it might be a problem of
> multi-queries - the framework does not accept non-select queries.
>
> Is the MultiQuery meant to be used for updates too? Or is it a bug I
> should report on NHibernate Jira?
>
> Thanks for any advice.
>
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