将引用不存在元素的元素插入数据库时使用哪个 HTTP 响应状态代码？

Question

I have a table with cities that has a foreign key constraint on another table, countries. What status code should I return if the client sends a POST request with a city that references a country that doesn't exist in the countries table? I was thinking 400 BAD REQUEST , but this seems to be related only to the syntax of the request.

Answer 1

404 Not Found would be a better option. With an error message "country not found".

Answer 2

You could use HTTP 422/Unprocessable Entity

The request was well-formed but was unable to be followed due to semantic errors.

The 400/Bad Request is too vague, but 404/Not found could also fit perfectly in your case.