How I can put a initial credit for customers?

[pabgp]

Hello,

 

How I can put a initial credit for customers? I have other aplication with other DataBase where customers have credits (credits = money) and I was exported this database and created a new table for have this data in the database of prestashop. Now I don't see where I can put (with sql sentence) this value of credits in a shield of customer table or other shield in other table as coupon...

I search guides and saw that there are many differences between prestashops versions. This version is 1.6, but is possible that I will must do it in 1.4

Are there anybody that know where are this shields of the prestashop database or any other form for do it?

Thanks.