I\'ve checked this question and it seems to be related to what I need, but does not answer it exactly.
I have an entity (Sql Compact using EF Code First via MVC3- if
If the CreateDate and CreatedBy fields are not in the edit form, the update action object will not have the db values.
The additional call to the db and resetting, as Ed's answer describes, can be avoided if you include those fields in the edit form. Then the normal model binding should pick them up and give them back to you on the update.