R – NHibernate Query problem

nhibernate

I'm quite new to NHibernate and starting to find my way around.

I have a domain model that is somewhat like a tree.

Funds have Periods have Selections have Audits
Now I would like to get all Audits for a specific Fund

Would look like this if I made it in SQL

SELECT A.*
FROM Audit A
JOIN Selection S ON A.fkSelectionID = S.pkID
JOIN Period P ON S.fkPeriodID = P.pkID
JOIN Fund F ON P.fkFundID = F.pkID
WHERE F.pkID = 1

All input appreciated!

Best Answer

Try this

select elements(s.Audits)
from Fund as f inner join Period as p inner join Selection as s  
where f = myFundInstance

Related Solutions

Best way to delete all rows in a table using NHibernate

In the TearDown of my UnitTests, I mostly do this:

using( ISession s = ... )
{
   s.Delete ("from Object o");
   s.Flush();
}

This should delete all entities. If you want to delete all instances of one specific entity, you can do this:

using( ISession s = .... )
{
    s.Delete ("from MyEntityName e");
    s.Flush();
}

Offcourse, there's a drawback with this method, and that is that NHibernate will first fetch the entities before deleting them.

R – NHibernate set properties automatically on save

Interceptors can do this:

http://www.nhforge.org/doc/nh/en/index.html#manipulatingdata-interceptors (9.10, link doesn't always work).

Cut/paste from the document:

public class AuditInterceptor : IInterceptor
{
    ...

    public boolean OnSave(object entity,
                          object id,
                          object[] state,
                          string[] propertyNames,
                          IType[] types)
    {
        if ( entity is IAuditable )
        {
            for ( int i=0; i<propertyNames.Length; i++ )
            {
                if ( "CreateTimestamp" == propertyNames[i] )
                {
                    state[i] = DateTime.Now;
                    return true;
                }
            }
        }
        return false;
    }

}

OnFlushDirty() could be used for UpdatedDate.

You are going to want every entity that has a CreatedDate/UpdatedDate to implement an interface so that the interceptor can check whether it should act (in the provided example it is IAuditable).

Edit

Just noticed chapter 11: Interceptors and events. You can inherit from EmptyInterceptor which makes things easier if you only need to override some of the methods.

I've never used Events.

Best Answer

Related Solutions

Best way to delete all rows in a table using NHibernate

R – NHibernate set properties automatically on save

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