Which symbols can/cant I use in a string?

I tried to use the Thai symbol for currency '฿' in a string. It seemed to save this just fine, however when I exit my project and restart it, it has replaced the symbol with a '?' Is there any way to know which symbols can/can't be used and is there any way to add symbols to the 'can use' list?
1 answers

My guess would be that the symbols you can save are probably defined by the character set of your database. What character set do you have selected?