[UPHPU] Database Question

[Webot Graphics]

I have a project which involves keeping a running inventory on all  
the products which the company I work for manufactures/uses/stores.

Currently this company uses MYOB (which I don't like) for it's P.O.S.  
system. Since they never used the inventory side of it there is no  
inventory associated with all the line items (part of why I don't  
like MYOB: they won't let you start to inventory an item after it has  
been created). The company has multiple sizes of each product, and  
each size has it's own line item.

--example--
item# 202 vanilla extract 1oz
item# 203 vanilla extract 2oz
item# 204 vanilla extract 4oz
item# 205 vanilla extract 8oz
item# 206 vanilla extract 16oz

So my question is: When I go to create a new database (because I  
can't find a way to access the MYOB Database, another reason I don't  
like MYOB) should I continue to have a separate line item for each,  
or have 1 table with the sizes in it, 1 table with the products in  
it, and 1 table that connects the two?

I haven't done any heavy database setups so I am new at this. What do  
you think?

Justin Giboney