F# data access and EF migrations

Question

I have been using F# for some time, and really liking it.

I want to use type providers for data access, but would love to have entity framework migrations.

Can I use EF migrations without entity framework? I am fine with writing migration code by hand, hopefully in F#.

Answer 1

In the case where you want to use EFCore, it's possible to isolate only the migrations in a C# project with MigrationsAssembly.

For example in a DbContext module:

let setupOptions (optionsBuilder: DbContextOptionsBuilder) =
    optionsBuilder.UseNpgsql(
        "Host=localhost;Database=mydb;Username=postgres;Password=postgres",
        fun opt -> opt.MigrationsAssembly "MyProject.Data.Migrations" |> ignore)
    |> ignore

Services configuration:

services.AddDbContext<DbContext.MyDbName>(DbContext.setupOptions)

CLI:

dotnet ef migrations add CreateFoo -p ./MyProject.Data.Migrations -s ./MyProject.Api -v    
dotnet ef database update -p ./MyProject.Data.Migrations -s ./MyProject.Api -v

There is also a work in progress project to support F# design-time: https://github.com/bricelam/EFCore.FSharp

Answer 2

F# type providers imply that there is already external data source i.e. they are inherently "Db First". Using EF Code First only to automatically generate migrations is not the best idea, I recommend plain SQL and some tools to keep track of migrations such as dbup. I answered it in details in similar but bigger question.

Answer 3

You can certainly use EF migrations without using EF in your app. Create a separate project and use Code First migrations.

I'm not aware that the migrations scaffolding feature supports F#. Either suffer with C# for migrations or translate the code yourself?