@MrMoody - Whatever language you use, I think the use of underscore marks for database field names is most likely the safest convention – even if your language allows you to use spaces.
Spaces are a big no-no in Microsoft Access. I work for a software company that uses Access and sometimes our customers will create spaces in their field names.
All I can tell you is that creates a host of problems. In my opinion, you can’t go wrong with underscore characters.