How does Oracle calculate balance at ending of period

 Hi everybody,

I want to know mechanism of calculation balance when closing period.

For examples :

1) Inventory :

- Is there any table store the balance of quantity, periodic cost for each Item? Does Oracle using offline balance in inventory ?

- In General, how does oracle calculate these balance after closing Period of Organization, Period of PAC ?

2) Payables :

- Is there any table store the liability balance of supplier after closing Payables period ? Does Oracle using offline balance for Payables?

- How does oracle calculate supplier's balance quickly ?

3) Receivables

- Is there any table store the liability balance of customer after closing Receivables period ? Does Oracle using offline balance for Receivables?