Front, Mid, or back-office? Being able to use databases is a great skill and one we look for. Not a fan of MS Access it is really a last case tool. Understanding how data structures work and SQL would be the best bet.
As a commodity desk we mainly use databases to build analytics to look at trends and project future patterns. We have a series of data updates that run overnight and input tons of info, such as daily weather/supply and demand #s/current prices/current future strip and so. Then we have models which use this data in a proper format. For instance I could pull 10 years of weather data for certain areas in the US and compare to pricing data, then compare to where the S/D of that commodity was and so on.