Nhibernate 保存对象的顺序

Question

I'm having a service which takes a one or more of entities, which has been deserialized from a file. These entities may or may not have a relation. Are there any easy way to ensure that Nhibernate handles the entities in the correct order when calling saving the entities? Right now I'm doing it with session.Save(entity) , but it may end up some times end up with an exception about " property pointing at a transient or null value.." .

Answer 1

In general, no, NHibernate will manage it for you automatically because it is considered the safe way. There are two options:

First option : You can perform a Flush method and make sure you have the executed over the database. For sample:

using (var session = sessionFactory.OpenSession())
{
    using (var transaction = session.BeginTransaction())
    {
        try
        {
            foreach (var item1 in data1)
            {
                session.Save(item1);
            }
            session.Flush(); // execute all the queries for the itens (1)

            foreach (var item2 in data2)
            {
                session.Save(item2);
            }
            session.Flush(); // execute all the queries for the itens (2)

            transaction.Commit();
        }
        catch (Exception e)
        {   
            transaction.RollBack();
            // do some log with `e` exception reference
        }
    }
}

Second option . If you just need to send it to the database without any state management, you could use ISessionStateless instead of classical ISession . You lose all the sesion state management that NHibernate does automatically. (lazy loading, first/second level caching, etc..). You just call method like Insert , Delete , Update a entity. Importante: You can have more performance with a StatelessSession give you make sure it is appropriate for your scenario:

https://nhibernate.info/doc/nhibernate-reference/batch.html