Hafner.Tools.Settable

Repository Hafner.Tools.Settable (formerly Hafner.Tools.SetTracker) provides a tiny helper type of the same name that can be used to differentiate between whether a parameter/property was set to null or was not set at all. Useful for

• Filters:

    public class AddressFilter {
  
        public Settable<String> FirstName { get; set; }
        public Settable<String?> MiddleName { get; set; }
        public Settable<String> Surname { get; set; }
  
    } 
  

  • not set: Do not apply any filter for that property
  • null set: Return all records that have null in the particular column

• UpdateRecord methods:

    public void UpdatePersonData(int personId, Settable<string> firstName = default, Settable<string?> middleName = default, Settable<string> surename = default) {
        //Add firstName, middleName and surename to query if set and execute it
    }
  

  • not set: Don't change the value
  • null set: Change the value to null

• Data Transfer Objects (DTOs):

    public class Person {
  
        public int PersonId { get; set; }
        public Settable<string> FirstName { get; set; }
        public Settable<string?> MiddleName { get; set; }
        public Settable<string> Surname { get; set; }
        public Settable<string?> ChangeHistory { get; set; }
    }
  

  • not set: Value was not loaded (e.g. the ChangeHistory might be omitted for performance reasons)
  • null set: The value is null in the database

etc.