(continued from Medium)

Create with source code and database A DDD CRUD Application with external database SQL Server in F#.NET.

Answer:

Sure! Here's an example of how you can create a DDD CRUD application with an external SQL Server database in F#.NET.

First, you will need to install the necessary dependencies. You can do this using the .NET CLI by running the following command:

dotnet add package Microsoft.EntityFrameworkCore
dotnet add package Microsoft.EntityFrameworkCore.SqlServer

Next, you will need to define your domain model. For example, let's say you have a Product entity with the following properties:

codetype Product =
    { Id: int
      Name: string
      Price: decimal }

You can then create a repository for the Product entity using the IRepository interface:

codetype IProductRepository =
    abstract member GetById: int -> Async<Product option>
    abstract member GetAll: Async<seq<Product>>
    abstract member Add: Product -> Async<unit>
    abstract member Update: Product -> Async<unit>
    abstract member Remove: int -> Async<unit>

To implement the repository, you will need to use Entity Framework Core. Here's an example of how you can do this using a context class and a Product entity:

codetype ProductContext() =
    inherit DbContext()

    let productTable = Set<Product>()
    member x.Products with get() = productTable

type ProductRepository(context: ProductContext) =
    interface IProductRepository with
        member x.GetById id =
            async { return context.Products.SingleOrDefault(fun p -> p.Id = id) }
        member x.GetAll() =
            async { return context.Products.ToList() }
        member x.Add p =
            async {
                context.Products.Add(p)
                context.SaveChanges()
            }
        member x.Update p =
            async {
                let entity = context.Products.SingleOrDefault(fun e -> e.Id = p.Id)
                if entity <> null then
                    entity.Name <- p.Name
                    entity.Price <- p.Price
                    context.SaveChanges()
            }
        member x.Remove id =
            async {
                let entity = context.Products.SingleOrDefault(fun e -> e.Id = id)
                if entity <> null then
                    context.Products.Remove(entity)
                    context.SaveChanges()
            }

Finally, you will need to configure Entity Framework to use your SQL Server database. You can do this by adding a connection string to your appsettings.json file:

code{
  "ConnectionStrings": {
    "ProductDb": "Server=localhost;Database=ProductDb;Trusted_Connection=True;"
  }
}

You can then use the ProductContext and ProductRepository classes in your application to perform CRUD operations on the Product entity.

I hope this helps! Let me know if you have any questions or if you need further assistance.

I want the same thing in multiple files

Sure! Here's an example of how you can split the code into multiple files:

Product.fs:

codetype Product =
    { Id: int
      Name: string
      Price: decimal }

ProductRepository.fs:

codetype IProductRepository =
    abstract member GetById: int -> Async<Product option>
    abstract member GetAll: Async<seq<Product>>
    abstract member Add: Product -> Async<unit>
    abstract member Update: Product -> Async<unit>
    abstract member Remove: int -> Async<unit>

type ProductContext() =
    inherit DbContext()

    let productTable = Set<Product>()
    member x.Products with get() = productTable

type ProductRepository(context: ProductContext) =
    interface IProductRepository with
        member x.GetById id =
            async { return context.Products.SingleOrDefault(fun p -> p.Id = id) }
        member x.GetAll() =
            async { return context.Products.ToList() }
        member x.Add p =
            async {
                context.Products.Add(p)
                context.SaveChanges()
            }
        member x.Update p =
            async {
                let entity = context.Products.SingleOrDefault(fun e -> e.Id = p.Id)
                if entity <> null then
                    entity.Name <- p.Name
                    entity.Price <- p.Price
                    context.SaveChanges()
            }
        member x.Remove id =
            async {
                let entity = context.Products.SingleOrDefault(fun e -> e.Id = id)
                if entity <> null then
                    context.Products.Remove(entity)
                    context.SaveChanges()
            }

appsettings.json:

code{
  "ConnectionStrings": {
    "ProductDb": "Server=localhost;Database=ProductDb;Trusted_Connection=True;"
  }
}

You can then use the ProductContext and ProductRepository classes in your application to perform CRUD operations on the Product entity.

I hope this helps! Let me know if you have any questions or if you need further assistance.

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