... now all data are stored, I did following code:

update my_table
set last = 'weber-williams'
where first = 'jonie';

now, all data on the column FIRST is gone...

btw, if i'd have two 'jonie' at first name would be following command correct if I assume there is only one LAST called 'weber'? -->

update my_table
set last = 'weber-williams'
where first = 'jonie' AND last = 'weber';

tia

cheers,
bs