Depends on your project and what you are going to do with them...Its kinda pointless to ask us since we don't know the system you are making. We can pull a random guess from our behind but that wouldn't be very useful. All in all, your question is way to vague for us to answer in any meaningful way.
Logic without the fatal effects.
All code snippets are licensed under WTFPL.
If you explained why you want to permanently store some of the session variables in a table, and how imagine your inventory system will benefit from having them, then you might elicit some ideas from us about the best way to go about it.