Question

I am writing a WCF Rest API that provides CRUD functionality to an entity say Student. Here is how it is defined:

class Student
{
  Guid Id;
  string Name;
  string LastName;
  string Age;
  DateTime DOB; 
}

My service contract is something like this:

class StudentService
{
  [WebInvoke(Method = "POST")]
  public void Add(Student student)
  {...}

  [WebInvoke(Method = "PUT")]
  public void Update(Student student)
  {...}

  [WebGet()]
  public void Get(string Id)
  {...}

}

Now the thing is that while updating a student record the client may not provide complete data. For e.g. it may provide Id and DOB but no name and LastName. Id being mandatory field. I need to know what could be the best approach/design in such a case?

I can fetch the existing record from db and perform a compare on both then update as necessary. The problem with this approach is that I have no way of knowing if a user actually wants to update a field to null. And then again, comparison does not seem a neat design. Any ideas?

Answer 1

After going through various strategies of handling this kind of thing I sort of implemented what was described in the answer to this question: Only update some properties on an EF entity that are not set to null.

In a nutshell I am tracking which properties were set during desrialization and then updating only those properties.