Entity Framework Code First - Reverse Engineer

Question

I am about to start work on a ASP.Net MVC 4 web application using Entity Framework Code First. Because the database already exists I am using Code First's ability to perform Reverse Engineering in order to generate my domain classes.

I wish then to place these domain classes into a separate project of their own within my solution in order to keep them persistence ignorant. However, when I run the tool to reverse engineer my database (using Entity Framework Power Tools), I find that the domain classes are created, but also created is a folder called Mapping containing a mapping class for each domain class which then uses Fluent APIs to map the table properties. This is all good.

But, what I have also found, is that the mapping classes rely on a reference to the Entity Framework and I was just wondering is this thought to be poor practice? Usually when I create POCO classes, they are completely persistence ignorant, ie, there has been no reference to Entity Framework in that project at all.

Your thoughts?

Thanks.

Husein Roncevic Husein Roncevic · Accepted Answer · 2012-12-21T09:58:31

You can keep your POCO classes in one project, while mapping stays in another project. Just add a reference to the project where POCO classes are located. Another approach is to create a data access layer and move mappings over there. That way you have three projects. Your main MVC project, your model project and data access layer that contains mappings and a reference to EntityFramework.

For example, your solution could be something like this:

1. Web User Interface (MVC)
2. Business layer
3. Unit of Work/Repository
4. Data access layer (Mapping from EF Reverse Engineering)

All four projects have access to the fifth project, Domain Model (Models from EF Reverse Engineering). Your 1 communicates with 2, 2 communicates with 3 and 3 communicates with 4. All four of these have a reference to Domain Model so you don't have to perform any type of domain model conversion between the layers.

By the way, I ignored service layer, but if you have web services or REST, you could fit it in another project, but let's not get into too many details.

Entity Framework Code First - Reverse Engineer

1 Answers