[GRASSLIST:6709] how to get other cats into other columns with v.to.db?!?!

[Dan Jacobson]

Here are some lines as seen with v.out.ascii:
L  7 2
...
 3     7
 1     1
L  8 2
...
 3     2
 1     2
$ man v.to.db shows one can easily get layer 1 into a table:
$ v.to.db map=soils type=area option=cat
but how in the world does one get layer 3 into another column in the table?!?!
Yes, the other column is already in the table. Now how to insert the
values?
v.to.db map=n10 option=cat col=oline layer=3
useless, as it tries to stick values in 'cat'.
cat|oline
1|0
2|0
how can I get
1|7
2|2