declare
   v_ID number;
begin
   -- First table
   select max(ID) into v_ID from FooBar;
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+1, 'a', 1, 'flort');
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+2, 'b', 2, 'zap');
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+3, 'c', 3, 'kazoo');

   -- Second table
   select max(ID) into v_ID from BarBaz;
   insert into BarBaz (ID, col1)
   values (v_ID+1, 'etcetera');
end;