Question

I am using Entity Framework. I have a table Person that has a foreign key on Table PersonCategory. Person Id is an auto-incremented identity (1,1). Each time i update the person entity the entity framework inserts a row for PersonCategory Table Even if category is found.

I am using Database first design.

class Person
{
  public string Name {get;set}
  public PersonCategory {get;set;}
}

class PersonCategory
{
  public int ID {get;set}
  public string Name{get;set;}
}

Answer 1

First you need to attach the existing PersonCategory to the context;

var myPersonCat = new PersonCategory { ID = 1, Name = "Foo" };
var myPerson = new Person { Name = "Bar", PersonCategory = myPersonCat };

context.PersonCategories.Attach(myPersonCat);    
context.People.Add(myPerson);