Currently, the only way to activate a client dataset at design time is to associate it with a provider, to load data from a file, or to assign data from another dataset. Typically, for a single tier application you would create the dataset at runtime using the CreateDataSet method. Here is how you might code the FormCreate and FormDestroy methods:

?

?OnFormCreate:?
if FileExists('MYDATCDS') then
   ClientDataSet.LoadFromFile('MYDATA.CDS') 
else
begin
  ClientDataSet.FieldDefs.Add('Field ', etc.); 
  ClientDataSet.FieldDefs.Add('Field2', etc.);
  ClientDataSet.CreateDataset;
end;
?OnFormDestroy:?
if ClientDataSet.Active then
begin
  // Next line is optional, 
  // if you don't want undo support you could
  // set LogChanges = False instead.
  ClientDataSet.MergeChangeLog; 
  ClientDataSet.SaveToFile('MYDATA.CDS');
end;
?