arrgh Help! Water mark on my new solid oak table

[FGM]

Some idiot friend of DH plonked a glass of water down on my lamp table- studiously ignoring all the coasters that were there. Now my table has a chunky white water ring.

It's solid oak with, I think, just an oiled finish.

How can I get rid of the ring?

Can I prevent it happening again?

www.ehow.com/how_5622593_water-rings-off-oak-table.html i used step 1 in the past with good results.

Baby wipes are often the key to success in any household task, I find.

Thanks- I'll start with the olive oil x