c# - NHibernate Criteria Search By Time Of Day -

i trying create nhibernate criteria me posts created during time of day. example, want posts created between times of 12:15:00 , 2:20:00.

post this

public class post {    public virtual datetime createdon { get; set;} } 

and mapping:

<class name="post" table="posts">    <property name="createdon" not-null="true"/> </class> 

and use detachedcriteria (this part of larger search) similar to:

var criteria = detachedcriteria.for<post>                .add(restriction.ge("createdon", time(12, 15, 00))                .add(restriction.le("createdon", time(2, 20, 00)); 

i know isn't @ correct shows trying accomplish. using sql server database.

if create query directly in sql use datepart function. this question inquires calling datepart function nhibernate. use nhibernate projection: projections.sqlfunction.

what complicates things little need have multiple projections, 1 hour, minute, , second (depending on granularity need). also, haven't found way call datepart directly since couldn't find way pass datepart parameter (its non-quoted string constant). instead, can extend dialect so:

  public class mssql2008extendeddialect : mssql2008dialect     {         public mssql2008extendeddialect()         {             registerfunction("datepart_hour", new sqlfunctiontemplate(nhibernateutil.datetime, "datepart(hh, ?1)"));         }     }  

edit: caution take note of query performance. since there no index on time of day, if there index on date column, query performance suffer if there many records , column being restricted on. in case might better add explicit columns hour/minute.