function to create unique key for rows?

I have a large table (@1M rows) with several columns of VARCHAR2 data that I would like to be able to create unique indexable keys for to speed look-ups.

For instance, now I do this:
Select myData From myTable Where col1=this and col2=that and col3=other

and I'd like to be able to say this:
Select myData From myTable Where
new_indexed_column={some_value_i've_created}

Does Oracle have a 'Hash' function of some type I can use to give each of these rows a unique indexable value?

Thanks. Received on Wed Oct 20 1999 - 18:21:42 CDT