single Column Update for multiple rows in oracle10g - oracle

Question

Update table_1 set col1= 1 where col2 = 'ONE';
update table_1 set col1= 2 where col2 = 'TWO';
Update table_1 set col1= 3 where col2 = 'THREE';
...
update table_1 set col1= 100 where col2 = 'HUNDRED';
Is there any simplified way to achive this in a single query instead of writing 100 update statemnets in oracle10g??

Answer 1

I think there might be a solution with Oracle Case-Statement or the decode-function, although it will be a quite long statement and I am not quite sure what the advantage over 100 update statements might be. Also I am not aware of any limitations regarding length of parameter-lists, etc.
Example for Case:
update table_1
set col1 = CASE col2
WHEN 'ONE' THEN 1
WHEN 'TWO' THEN 2
WHEN 'THREE' THEN 3
WHEN 'FOUR' THEN 4
WHEN 'FIVE' THEN 5
WHEN 'SIX' THEN 6
WHEN 'SEVEN' THEN 7
WHEN 'EIGHT' THEN 8
...
WHEN 'HUNDRED' THEN 100
ELSE col2
END;
Example for decode:
update table_1
set col1 = decode(col2,
'ONE', 1,
'TWO', 2,
'THREE', 3,
'FOUR', 4,
'FIVE', 5,
'SIX', 6,
'SEVEN', 7,
'EIGHT', 8,
...
'HUNDRED', 100,
col2);

Answer 2

You could make use of the Julian spelling formats (search asktom.oracle.com for more details)
Here's output from my session:-
create table table_1 (col_1 number, col_2 varchar(20))
insert into table_1 (col_1, col_2) values (null, 'THIRTY-THREE')
insert into table_1 (col_1, col_2) values (null, 'SEVEN')
insert into table_1 (col_1, col_2) values (null, 'EIGHTY-FOUR')
select * from table_1
COL_1 COL_2
THIRTY-THREE
SEVEN
EIGHTY-FOUR
update /*+bypass_ujvc*/
(select t1.col_1, spelled.n
from
table_1 t1
inner join
(select n, to_char(to_date (n, 'J'),'JSP') spelled_n from
(select level n from dual connect by level <= 100)) spelled
on t1.col_2 = spelled.spelled_n
)
set col_1 = n
select * from table_1
COL_1 COL_2
33 THIRTY-THREE
7 SEVEN
84 EIGHTY-FOUR
The nasty hint (bypass_ujvc) ignores the fact that the inline view isn't key preserved - in practice you should use a merge statement instead. But this isn't a real-world scenario, right! (And you'll have to treat your 'HUNDRED' as a special case = 'ONE HUNDRED'.)