Entity Framework Core Using multiple DbContexts

Solution 1:

I figured it out. This mostly came about because I accidentally deleted the database that Identity was using and I needed to figure out how to get it back.

Apparently there's nothing wrong with my connection string the way it is. I just needed to go into the package manager and type these commands in this order:

1. Add-Migration init -Context PartsDbContext
2. Update-Database -Context PartsDbContext

I found this out because that is what I had to do to get my ApplicationDbContext working again and it turns out that this step is done for you when you create a new MVC Core Web Application in Visual Studio using Individual User Authentication.

So basically the steps for adding more DbContexts is to:

1. Create a DbContext Class
2. Create a Connection string for that DbContext in appsettings.json
3. Add the DbContext to your configured services in Startup.cs
4. Setup the DbContext in the controllers that will use it.
5. Open the package manager and run the 2 lines above. (if "-Context" doesn't work try "--context"
6. Run your program and let EntityFrameworkCore take care of the rest.

Solution 2:

First of all, thanks @Joe Higley answer this questions,I want to add more situation to help more people.

My situation is i'm trying to use EF-Identity and Area to create a admin panel, in my admin area own their own controller/models/views..., also contain a new DBcontext.

There is problems, if you try to context.Database.EnsureCreated(); to initialize DB there will show

System.Data.SqlClient.SqlException: 'Invalid object name 'fieldName''

Ref this link Migrations with Multiple Providers

We can use migrations and use --context to set which DbContext you want to run

In VScode you can run

dotnet ef migrations add InitialCreate --context BlogContext
dotnet ef database update

In Package Management Console you can run

Add-Migration InitialCreate -Context BlogContext
Update-Database