Hashing on more than one attribute?

[Marc Lepage <mlepage@...>]

I know it's trivial to hash on a single value, by putting it into a table field. I want to effectively store a composite key in a table: say, a string, a number, and another string.

Is there a way I can somehow produce a single hash of that combination of three values, to use as a key in a field? Something not obvious? Or must I effectively have a few levels of tables to hash 3 values? (And more for 4, 5, 6 values...)

Thanks,

Marc