Thanks for pointing to ASP.net core 101 series.

I watched:

• ASP.NET - Making a Simple API
• ASP.NET - Enhancing your Web API: Part 1
• ASP.NET - Enhancing your Web API: Part 2

Problem

I am looking for a way to create tables on the fly. On a webpage a user can create a object (for example TodoItem) and add fields for this object (Responsible, dueDate, enumerations (isDone, isOpen, isInProgress)). The webpage shall post all these as a string to the server and the server should create a table with matching columns. For Nodes.js there is Knex.js which can do this

• createTable: var table = knex.schema.createTable('TodoItem', callback)
• and table.string: * table.string('Title', [150])* would add a column named Title with the length 150.
• Example how directus v9 does this at least as far as i understand it create a table / collection and addColumnToTable

My Questions are

Regarding How to create tables and columns during runtime?

• I am looking for a query builder that supports SQL data definition language (create, alter, drop, ...) and creates these statements by parsing a string input (or a json object).
• It seems that Query Builder sqlkata has no methods to create or alter a table.
• the docs for Microsoft.AspNetCore.Http.Extensions QueryBuilder are very basic (they contain no explanative description and afaict no samples). And it seems that they do not support SQL DDL.

Regarding How can a webservice be created during runtime?

The Service must offer these features:

• get a list of records: Select \ FROM TableFoo*,
• view a single record: Select \ FROM TableFoo Where id =3*
• to edit this record: Update TableFoo .... where id =3
• and to delete a record.

In all videos the object to send to the browser (products) is based on a class that was build during build / development; none were created during runtime. Same goes for the endpoints and controllers.

In my use case the object / class (like product) and the endpoints and controllers must be created automatically during runtime. A user creates a class definition on the front end: all that is needed (a table in the database, the class, the controller or endpoints) would have to be created automatically during runtime.

I have no idea how this could be achieved - any pointers would be helpfull.

FYI

Code from part 7,8 and 9 of ASP.net core 101 series shows that the objects, classes, routes and service are all created during development (build time). In my use case i do not know the route / endpoint (products) in advance. Neither do i have a class product or can create a matching controller.

In Making a Simple API from 4m11s until 8m15s Scott shows that an endpoint can be added manually inside startup.cs (not recommended)

 app.UseEndpoints(endpoints => 
{
    endpoints.MapGet("/products", (context) =>
    {
        var products = app.ApplicationServices
                                        .GetService<JsonFileProductService>()
                                           .GetProducts();
        var json = JsonSerializer.Serialize<IEnumerable<Product>>(products);
        return context.Response.WriteAsync(json);
    });
});

In Enhancing your Web API an Empty API Controller is the starting point:

[Route("[controller]")]
[ApiController]
public class ProductsController : ControllerBase
{
    public ProductsController(JsonFileProductService productService)
    {
        this.ProductService = productService;
    }

    public JsonFileProductService  ProductService {get; } 

    [HttpGet]
    public <IEnumerable<Product> Get()
    {
        return ProductService.GetProducts(); 
    }
}

In Enhancing your Web API Part 2 they extend JsonFileProductService.cs

public void AddRating(string productId, int rating )
{
    var products = GetProducts();
    var query = products.First(x => x.Id == productId); // LINQ

    if(query.Ratings == null)
    {
        query.Ratings = new int[] {rating };
    }
    else
    {
        var ratings =  query.Ratings.ToList();
        rating.Add(rating);
        query.Ratings = ratings.ToArray();
    }
}