Well it does, you just change it in the memory and then save everything when the player disconnects. My data layer does this.
I'm attaching my current version which you can try out if you want. Just hook up a database to the SQL_MakeDbTuple native, go to the server, write addclass to the console a couple of times to add random data, then getclass which will loop through all of the currently cached data and print it to your console and saveclass to save it into the database. That's the functionality the data layer will have, so I really recommend you to wait it out, it's DESIGNED for stuff like player inventories.
It's not made for actual use, but it won't take me more than a few days to completely finish it and release it.