Problem with upgrading my themes/modules : quantity of products

[creacom]

I've done a prestashop shop for a friend about a year ago, where i deveolopped some custom modules, in a prestashop 1.4.4.1 version.

It worked well.

 

Now i want to make it work in 1.5.2 but i'm confronting many problems :

For one, I have imported products, with quantity = 1, and in the admin pannel, they are displayed with a quantity = 1, but when i look in the database in the ps_product table, the 'quantity' field for all products is = 0 !

So my modules (that worked in P1.4) using that field are broken in P1.5.2

 

Is ps_product.quantity obsolete ? is it used for anything else ?

But most important for me in which table/field should i get the quantity for a product ? I've looked in all ps_product_xxx tables and not found it

 

Thanks in advance