title: how does paypal keep their database secure?
body: <p>first off, I am not trying to hack paypal.  What I'm trying to do is to create a similarly safe database.</p>
  
  <p>OK, so if i sign up with paypal, i can 'deposit' money into my paypal account from my credit card or from my bank account if i have that set up.  When this happens money is transfered from myself to paypal.  But not really into my paypal account.  That is my pay pal account is not an actual physical space with gold sitting in it.  Unless I am wrong, what happens here is my account is in a databse table on paypal's servers, and when I make a deposit, they simply change the 'balance field' from whatever to += my deposit.  So, if anyone were to be able to hack into this db, they could increase their balance by anything they wanted simply by changing the value in the 'balance field.'</p>
  
  <p>How does paypal go about making sure this cant happen, and what kind of db system do you tink they use.  I would guess NOT MySQL, correct?</p>
  
  <p>Thanks all.</p>