c# - asp.net Entity Data Model doesn't have submitChanges -

i start work linq, dbcontext doesn't have submitchanges method. should default in class. right?

    using system; using system.data.entity; using system.data.entity.infrastructure;  public partial class libraryentities : dbcontext {     public libraryentities()         : base("name=libraryentities")     {     }      protected override void onmodelcreating(dbmodelbuilder modelbuilder)     {         throw new unintentionalcodefirstexception();     }      public virtual dbset<user> users { get; set; }     public virtual dbset<msreplication_options> msreplication_options { get; set; }     public virtual dbset<spt_fallback_db> spt_fallback_db { get; set; }     public virtual dbset<spt_fallback_dev> spt_fallback_dev { get; set; }     public virtual dbset<spt_fallback_usg> spt_fallback_usg { get; set; }     public virtual dbset<spt_monitor> spt_monitor { get; set; }     public virtual dbset<book> books { get; set; } } 

when try call submitchanges, says method not exist. know why?

int id = (int)httpcontext.current.session["userid"];      var query = (from u in db.users                  u.id == id                  select u).firstordefault();      query.firstname = firstnamemodal.text;      db.submitchanges(); 

the method you're looking called savechanges.