Object-to-relational mapping the Entity Framework way: Code First Execute(script: true, export: false, justDrop: false) E.g.: // parameters : script = write out to schema.sql file. This can be handy if you're working on a new application where the database hasn't been created yet or to keep an up-to-date database creation script under source control. If needed, you can also create a new SchemaExport instance, passing in your Configuration object and call its Execute() method to generate a SQL script creating your database schema based on the mappings you defined and / or execute that script to create the database on-the-fly for you.
Nhibernate mapproxy how to#
If you were working against multiple databases, you'd have one SessionFactory instance per database, each containing the mappings for that database and able to create new Session instances that know how to generate and execute SQL queries against that database. It's thread-safe and typically used as a singleton. The SessionFactory instance in NHibernate is responsible for holding onto the compiled mappings and for creating new Session instances on demand. This is typically done once on application startup. Once your mappings are defined, you can then just create a Configuration instance, add your mappings to this configuration object and call its BuildSessionFactory() method to create a SessionFactory instance. You can do it either using XML (if you enjoy pain), using the built-in but undocumented fluent API or using the excellent fluent API provided by the third-party Fluent NHibernate library. You then define the mappings between your domain model objects and their relational representations. This part is unrelated to NHibernate and there should be nothing NHibernate-related in your domain model classes. You start off by defining your domain model using plain C# classes (or POCO rather since it doesn't have to be C#). With NHibernate, mapping your object model to your relational model is a fairly simple and logical process and one that your will see implemented in a very similar manner in just about every NHibernate-based application.
Object-to-relational mapping the NHibernate way Let's go through a very quick refresher on how NHibernate deals with this issue and see how it compares with Entity Framework.
With EF, it's also the first hurdle: should you adopt a Database First, Model First or Code First mapping workflow? With Entity Framework - just like with every other ORM, your first task is to map your object model to your relational model. Database First, Model First, Code First, oh my If you consider yourself an NHibernate veteran and are taking on your first EF project, this should save you some time.
Nhibernate mapproxy series#
This series attempts at filling some of the void. As soon as you venture out of the non-trivial territory, SO answers to EF-related questions tend to be tentative, incomplete, superficial, out-of-date or just plain wrong. And to be completely honest, the answers there rarely surprise by their brilliance. When you google an EF-related question, all you get are Stack Overflow questions. There is unfortunately no Oren Eini equivalent in the Entity Framework world. And you know that it will show up as the first result when you google it. In the NHibernate world, you know that no matter what your question is, Oren Eini (who goes by the pseudonym Ayende Rahien) will have already written a clear, precise and concise blog post addressing it. Entity Framework's rather poor documentation didn't help much.
However, I had to spend quite some time researching many of the finer points before starting to feel confident with EF and happy to let it manage my data. The transition from NH to EF6 was fairly smooth as they are conceptually very similar. It's definitely now a very credible alternative to NHibernate. EF6 has become not just a usable but a very capable ORM. But I have to say that Entity Framework has come a long way since then. I quickly abandonned it as it became clear very quickly that it wasn't ready for prime time. I had actually already given Entity Framework a try back in the EF4 days. IntroductionĪfter having used NHibernate quite extensively for the past few years, I've just completed my first 6 months in the Entity Framework world. Although this series is primarily aimed at NHibernate veterans making the transition to Entity Framework 6, any developer new to EF will probably find most of this information helpful too. This is the first part of an n-part series on using Entity Framework 6 coming from an NHibernate background.
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