xamarin - SQLite.Net Update generating error "it has no PK" -

i'm using lync syntax in pcl using xamarin.

public class settings {      [primarykey, autoincrement]     public int id { get; set; }      public string user_name { get; set; }     public string password { get; set; }     public string server { get; set; }  }  void createtables() {     database.createtable<settings>(); }  void insert() {          settings s = new settings();      s.server = "<none>"      s.user_name = "";      s.password = "";      database.insert(s) }  void update() {      settings s = database.table<settings>().firstordefault();      s.server = server_address.text;      s.user_name = user_name.text;      s.password = pass.text;      database.update(s) } 

i cannot update settings: has no pk when updating inserting works fine. i'm using xamarin in pcl referencing sqlite.net. i'm new sqlite , xamarin please verbose when asking more detail.

update - resolved

the class in same namespace place create instance of database object. adding "sqlite" attribute fixed issue strange.

[sqlite.primarykey, sqlite.autoincrement]