Creating custom conventions

Entity Framework Code First (4.1) introduced mapping conventions. Basically, Entity Framework would figure out certain patterns from the domain model and would configure things appropriately. In subsequent versions, these conventions were made customizable, meaning one could define and apply bespoke ones for our specific use cases. This is very useful, because it prevents us from writing the same code over and over. Some examples of custom conventions might include the following:

• Defining the maximum length for string properties

• Showing whether certain properties are mandatory or not

• Automatically setting cascading behaviors

Unfortunately, version 1.0 of Entity Framework Core dropped this; fortunately, it is still possible to achieve with some extra work.

Getting ready

We will be using the NuGet Package Manager to install the Entity Framework Core 1 package, Microsoft.EntityFrameworkCore. We will also be using a SQL Server database to store the data, so we will also...