Should/can one generate a database schema of ones classes?

Question

I have designed some classes using Visual Studio class diagramming. Now I would like to persist this data using ORM and maybe other persistence mechanisms. I am wondering if there is a way to generate the SQL based on the properties in my classes, since they fairly well represent the database structure needed. This would save me a lot of manual SQL typing, and give me a nice start.

I didn't start with the database model because I want to have my persistence decoupled from the actual "domain layer" (not sure if this is the correct naming).

The ORM mapper(LLBLGen) can then generate the coded based on this schema, and I'll only have to map the generated objects to my persistence interface.

Is the a good idea, or am I on the wrong path here?

I have found a tool that seems to do the job(MindScape LightSpeed), but unfortunately it's only available for VS2008.

Answer 1

It depends. If the project is small, and you have a tight deadline. Sure. However, generated code is almost always less maintainable than hand written code. This is the same for database schema generation. Have a look at your project scope. Maybe even generate the database, and see if you like how it looks. Then decide for yourself. Re evaluate for your next project. One size doesn't fit all.

Answer 2

It's a bad idea. Class design and database design are not the same thing.

Personally, I do my design at the conceptual level with NORMA, a free Visual Studio add-in. It will generate the schema from the conceptual model, and can also generate classes.

The classes it generates are a bit heavy for my tastes, but it turns out the code generation can be customized, if you don't fear XSLT.

Because of the nature of Object-Role Modeling, the constraints you place on the model can be used to infer both the database schema, and a "class" model as well.

Answer 3

There are many ORMs that can generate database schema from domain model classes. Moreover there are some ORMs that are designed especially for such way of development. It is "Model First" or "Code First" concept, and some people think that it is a future of database applications development, since LINQ is replacing SQL now. For example next version of Entity Framework will fully support this concept. I can recommend to try DataObjects.Net, it automatically generates and upgrades database schema and supports LINQ queries.