Skip to main content

NHibernate–Persist vs Save

While reviewing some code today I noticed that a developer was using the NHibernate session.PersistAsyc() method to save an entity in the database. I always used the session.SaveAsync() method so I was kinda intrigued about the difference between the two.

Let’s first talk about how they are the same; both methods make a transient instance persistent. This means that a new object created somewhere inside your code will be inserted into the database using an INSERT statement.

The picture below explains the different states of an NHibernate object quite well:

nhibernatestates

The differences

Ok, now we know in which way they are the same. How are they different then?

  • The SaveAsync() method returns the persisted object whereas the PersistAsync() method returns nothing.
  • The PersistAsync() method doesn't guarantee that the identifier value will be assigned to the persistent instance immediately, the assignment might happen at flush time. This means that when calling the SaveAsync() method, the INSERT operation is executed immediatelly.
  • Calling SaveAsync() on a detached entity will result in a new INSERT statement whereas calling PersistAsync will throw an exception.
  • Calling PersistAsync() outside of transaction boundaries will do nothing whereas doing the same using SaveAsync will result in the execution of an INSERT statement.

If you know more differences, please feel free to share…

Labels:

Popular posts from this blog

.NET 8–Keyed/Named Services

A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services. This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy. To support this feature a new interface IKeyedServiceProvider got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance: object? GetKeyedService(Type serviceType, object? serviceKey); object GetRequiredKeyedService(Type serviceType, object? serviceKey); To use it, we need to register our service using one of the new extension methods: Resolving the service can be done either through the FromKeyedServices attribute: or by injecting the IKeyedServiceProvider interface and calling the GetRequiredKeyedServic...
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...
Read more