Store as satoshis: BIGINT
Manipulate as satoshis
Then you can convert in any type (BTC, mBTC) based on user preference only for display.
im using BIGINT on my faucet project. you can play however you want with satoshi. but sometimes im getting errors. for ex: i have 50000 in the cell. divide 100000000 i get output like 0.00049999 for solve this error im writing convert function. im still working on it.