python - Django ternary relationships -

i quite new django , having troubles creating right models particular problem.

i have users, , own "wallet". wallet should list of currencies/values.

currencies in table "name" field. id : 1 name : eur

and i'd wallet : currency : eur, value : 0, currency : usd, value : 1000

for this, i'd use ternary table let's balance. balance have : wallet id : 1, currency id : 1, value : 50

i want right thing here, , not sure how proceed.

thanks

class wallet(models.model):     # if user has 1 wallet     user = models.onetoonefield('user')     # if user has multiple wallets     # user = models.foreignkey('user')  class balance(models.model):     currency = models.charfield(max_length=10)     value    = models.decimalfield()     wallet   = models.foreignkey('wallet')  # user's wallet: user_wallet = user.wallet # balances user_balance = user.wallet.balance_set.all() 

edit:

currency doesn't have model on own, because there aren't many currencies in there. can avoid joining additional tables when query. use choices on charfield instead:

currencies = (     (u'usd', u'us dollars'),     (u'eur', u'euro'),     # ... )  currency = models.charfield(max_length=3, choices=currencies) 

but again, if have lot of currencies, go model.

if using oneonone relationship between wallet , user, doesn't matter it. if have multiple wallets 1 user, think should figure out why user in wallet, right?