Best approach to update sql table with many optional fields with different types?

I am trying out this lib on a project with Giraffe.

One use case is that a web app needs to submit an update request with a dozen fields that are mostly optional. The request comes in in JSON through JS fetch. The REST api handler will bind the payload to a record with optional fields defined as int option or string option. If a field comes in as None, then the update sql should skip the field.

Is there a recommended approach to model the request payload and build up the update sql in a unified way?

It is easy with dynamical language such as js or Clojure. But I am not sure if there is a good way with F#.

Thanks in advance and my apology if it is a naive question. I did a search but couldn’t find out good answers.

[lanyusan]

Thanks. Would try Analyzer later.

[Zaid-Ajaj]

Well, there are a couple of reasons. Mainly because when you couple types (code) to database tables, that doesn’t necessarily make your code “type-safe” because now changes in the code break the application if these changes aren’t also reflected the database. This is something that the compiler cannot enforce so although your program compiles and maybe your unit tests will work too, the program will break in production because it relied on types being in sync with the database.

I’m not saying reflection is always bad, only prefer not to use it when possible or be very mindful of the points of failure.

Another reason not to use reflection is to be able to easily map table columns to other types, for example reading a jsonb column into string first, then converting it to JToken (from Newtonsoft.Json library) or reading timestamp as ZonedDateTime without extra plugins.

Finally, using this methodology of writing the data access layer makes the code very simple and allows for tools to better work with it: checkout Npgsql.FSharp.Analyzer

Hope this helps, let me know if you have more questions 😄