Entity Framework - What is the difference between With Entitystate.Modified and Without Entitystate.Modified?

Question

What’s the difference between the two ?

With Entitystate:

var registro = db.MinhaTabela.Where(a => a.MeuCampo == "Valor_Antigo").FirstOrDefault();
registro.MeuCampo = "Valor_Novo";
db.Entry(registro).State = EntityState.Modified;
db.SaveChanges();

Sem Entitystate:

var registro = db.MinhaTabela.Where(a => a.MeuCampo == "Valor_Antigo").FirstOrDefault();
registro.MeuCampo = "Valor_Novo";
db.SaveChanges();

Looks like they both work the same thing or it’s different ?

Answer 1

The State informs the Entity Framework the state of its object. In its first example, it is not necessary to set the State: Entity Framework itself will do it for you.

But in case you are "disconnected" from the database, that is, create an object out of context, as @virgilionovic mentioned in the comment, you can use the State to inform what the Entity Framework will do to the object when trying to save it.

Anyway, this has an drawback: all attributes will be changed. In the second example, the Entity Framework did the tracking of your object, and know that only need update "Meucampo", while in the first, all fields will be updated, even if they have not been changed. In addition to changing unnecessary fields, it may have other consequences, if for example your bank has constraints in some of the fields that will be validated, making the update process slower.