List of Record type matching issue Oracle

Is there a reason that you need dynamic SQL, a collection, and a loop to iterate over the collection? It sounds like you just want to check whether the row exists which can be done with a simple count (you could make the check more efficient by writing it as a where exists but that’s probably not important here)

declare
  p_workspace VARCHAR2(100):='WS-38515';
  l_num_workspaces integer;
begin
  select count(*)
    into l_num_workspaces
    from WMSYS.all_workspaces 
   where workspace = p_workspace;

  if( l_num_workspaces = 0 )
  then 
    dbms_wm.CreateWorkspace(p_workspace,isrefreshed=>TRUE);
  end if;
end;

Of course, you could also just skip the check, call CreateWorkspace, and handle the exception when it already exists. If you expect that the vast majority of the time you’re going to create the workspace, that might be more efficient.