Maintain Entity Framework Core DbContext in a Separate Project

Usually, when I have an application that has an API and a Database managed with EF, I really don't like to have the Application DbContext and all the Migrations inside the API project. It's actually very easy to split it out, this is a quick post on how we can maintain Entity Framework Core DbContext in a separate project. 

I have created a Solution WebApplication1 which has 2 projects, one is ASP.NET Core Web API and the other one just a .NET Core Class Library where I am maintaining Database specific things.

Solution

For WebApplication1.Data project, I have installed Microsoft.EntityFrameworkCore.SqlServer package and my WebApplication1.Data.csproj looks like this.

<Project Sdk="Microsoft.NET.Sdk">
 
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>
 
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.2" />
  </ItemGroup>
 
</Project>

And I have a very simple ApplicationDbContext.

using Microsoft.EntityFrameworkCore;
 
namespace WebApplication1.Data
{
    public class Employee
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }
 
    public class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext(DbContextOptions options) : base(options)
        {
        }
 
        public DbSet<Employee> Employees { get; set; }
    }
}

Then inside my WebApplication1.Api project, I have referenced WebApplication1.Data project and installed Microsoft.EntityFrameworkCore.Tools package there. This is very much required. This is my WebApplication1.Api.csproj looks like.

<Project Sdk="Microsoft.NET.Sdk.Web">
 
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>
 
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.2" />
  </ItemGroup>
 
  <ItemGroup>
    <ProjectReference Include="..\WebApplication1.Data\WebApplication1.Data.csproj" />
  </ItemGroup>
 
</Project>

I have the Connection String inside appsettings.json and setup the ApplicationDbContext inside Startup.ConfigureServices method.

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
 
    services.AddDbContext<ApplicationDbContext>(options =>
    {
        options.UseSqlServer(Configuration.GetConnectionString("ApplicationDbContext"));
    });
}

So basically that's it. Using the Package Manager Console in Visual Studio, I can run Add-Migration command targetting WebApplication.Data project.

Package Manager Console

Or alternatively using dotnet ef global tool (you need to install the tool first). The parameters are self-explanatory.

 dotnet ef migrations add Initial --project .\WebApplication1.Data\WebApplication1.Data.csproj --startup-project .\WebApplication1.Api\WebApplication1.Api.csproj                                                

And it will add all the Migrations inside WebApplication.Data project which is what I wanted.

Migrations

To apply the migrations,  again using the Package Manager Console in Visual Studio, I can run Update-Database command targetting WebApplication.Data. Or using the CLI,

dotnet ef database update --project .\WebApplication1.Data\WebApplication1.Data.csproj --startup-project .\WebApplication1.Api\WebApplication1.Api.csproj

That was easy.

Happy Coding.

Regards,

Jaliya