Date Validation Problem

Question

My Problem is during a transformation a field in the source table which is varchar2(6) is being populated into target table field whose data type is date. In the transformation they are checking if the source field is a valid date and only then they are populating that field to the target.
As it is done in Informatica they could easily finish the transformation with a built in function is_date.
How to do the same in Oracle. I just write simple SQL statements and test the data. I attempted to write it in the following way.
select key_field,to_Date(prcs_Date,'MMDDRR')
from table1
where Prcs_date is a valid date.
Please some one give an idea as it is very very urgent. I got struck up with this since last three hours

Answer 1

You can write your own is date function to check whether a value is a valid date.
See example below:
Good luck,
Jan-Marcel
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create table test_data (col_1a number, col_2a varchar2(6));
insert into test_data (col_1a, col_2a) values (1, '011505');
insert into test_data (col_1a, col_2a) values (2, '021505');
insert into test_data (col_1a, col_2a) values (3, '031505');
insert into test_data (col_1a, col_2a) values (4, '041505');
insert into test_data (col_1a, col_2a) values (5, '051505');
insert into test_data (col_1a, col_2a) values (6, '061505');
insert into test_data (col_1a, col_2a) values (7, '071505');
insert into test_data (col_1a, col_2a) values (8, '081505');
insert into test_data (col_1a, col_2a) values (9, '081599');
-- invalid date format
insert into test_data (col_1a, col_2a) values (10, '150805');
insert into test_data (col_1a, col_2a) values (11, 'JAN105');
commit;
create table new_data (col_1b number, col_2b date);
create or replace function is_date(p_date in varchar2, p_date_format in varchar2)
return varchar2 is
l_date_check date;
begin
l_date_check := to_date(p_date, p_date_format);
return('TRUE');
exception
when others then
return('FALSE');
end;
insert into new_data
(col_1b
,col_2b)
select col_1
, to_date(col_2, 'MMDDRR')
from (select col_1a col_1
, col_2a col_2
from test_data
where is_date(col_2a, 'MMDDRR') = 'TRUE');
commit;