c# - DbSet.Add to ignore properties that is not set -

using efcore, model has table foreign key constraints, refers table, column nullable. models this:

public class order {     [key]     public int id { get; set; }     public int code { get; set; }     public int amount { get; set; }     ... // other fields } public class ordercode {     [key]     public int id { get; set; }     public int code { get; set; }     public string description { get; set; } }  order o = new order { amount = 1 }; // code not set , default null in db orders.add(o); db.savechanges(); // failure 

so case code empty , default null in database, when add objects via dbset.add, threw exception:

microsoft.entityframeworkcore.dbupdateexception: error occurred while updating entries. see inner exception details. ---> system.data.sqlclient.sqlexception: insert statement conflicted foreign key constraint "fk_orders_code". conflict occurred in database "store", table "dbo.ordercode", column 'id'.

it looks efcore try add field in insert statement not set, there way avoid that?

i think should use int? code in model. default value int 0 entity framework sets code field.

public class order {     [key]     public int id { get; set; }     public int? code { get; set; }     public int amount { get; set; }     ... // other fields }