I want to create hierarchical tables (4 levels, but of course the possibility to have a level 5 will be better)

What is best method ?

Let’s say Tables to organize a toy-factory

----------------
One table >>>
Toy :

Id_toy
IdSup (the Id of superior element)
Level (1 to 4)
Name
----------------
4 tables >>>
Toy1 :

Id_toy1
Name
--------
Toy2 :

Id_toy2
Id_toy1
Name
--------
Toy3 :

Id_toy3
Id_toy2
Name
--------
Toy4 :

Id_toy4
Id_toy3
Name
----------------
One table >>>
Toy :

Id_toy
Hierarchy (with separtors like : 4,21,224,6458)
Level (1 to 4)
Name
----------------
One table >>>
Toy :

Id_toy
Level_1
Level_2
Level_3
Level_4
Name

(a 0 for no level) like : 4 | 21 | 0 | 0 , for level 2
----------------
5 tables >>>
Toy1 :

Id_toy1
Name
--------
Toy2 :

Id_toy2
Id_toy1
Name
--------
Toy3 :

Id_toy3
Id_toy2
Name
--------
Toy4 :

Id_toy4
Id_toy3
Name
--------
Toys :

Id_toys
Id_toy1
Id_toy2
Id_toy3
Id_toy4
-----------------

Another way ?



Thank you