Insert Birthdate with only YY format for period before 2000 Oracle DB - oracle

Question

I have afile where i recieve Birthdates and insert them into my Database.
the format is like the following
03-JUN-52
I use the following script to insert the date
update data."PersonBDates" set BIRTHDATE = to_date('13-SEP-47', 'DD-MON-YY');
and i also used
update data."PersonBDates" set BIRTHDATE = to_date('13-SEP-47', 'DD-MON-RR');
but when i check if find it 2074 not 1947.
How to insert this date into my oracle database?

Answer 1

Generally speaking, RR should work, but - not in all cases. You'll have to fix data first because RR will return different values:
for years from 00 to 49 you'll get this century, 20xx, while
50 to 99 will return previous century, 19xx
Here's an example:
SQL> alter session set nls_date_format = 'dd.mm.yyyy';
Session altered.
SQL> select
2 to_date('03-07-52', 'dd-mm-rr') rr1,
3 to_date('03-07-52', 'dd-mm-yy') yy1 ,
4 --
5 to_date('03-07-47', 'dd-mm-rr') rr2,
6 to_date('03-07-47', 'dd-mm-yy') yy2
7 from dual;
RR1 YY1 RR2 YY2
---------- ---------- ---------- ----------
03.07.1952 03.07.2052 03.07.2047 03.07.2047
SQL>
As you can see, both RR and YY format mask for year 47 return 2047.
What to do? Concatenate 19 to all years, e.g.
SQL> with test (col) as
2 (select '03-07-52' from dual union all
3 select '03-07-47' from dual
4 )
5 select col,
6 to_date(substr(col, 1, 6) || '19' || substr(col, -2), 'dd-mm-rrrr') result
7 ---------------- ---------------
8 -- this is "03-07-" "19" the last 2 digits
9 --
10 from test;
COL RESULT
-------- ----------
03-07-52 03.07.1952
03-07-47 03.07.1947
SQL>
[EDIT]
If your current inserting script works OK - which I doubt, regarding error code you mentioned in a comment:
ORA-01858: a non-numeric character was found where a numeric was expected
which means that not all input data have the same, expected & correct format of DD-MON-YY, then a simple way to fix birthdates might be this:
subtract 100 years from all dates whose year is larger than 2000
Here's how:
SQL> create table test (birthdate date);
Table created.
SQL> insert into test
2 select to_date('03-07-52', 'dd-mm-rr') from dual union all
3 select to_date('03-07-47', 'dd-mm-rr') from dual;
2 rows created.
SQL> select * from test;
BIRTHDATE
----------
03.07.1952
03.07.2047
SQL> update test set
2 birthdate = add_months(birthdate, -100 * 12)
3 where extract (year from birthdate) > 2000;
1 row updated.
SQL> select * from test;
BIRTHDATE
----------
03.07.1952
03.07.1947
SQL>
You can modify that, of course, if there's someone who actually was born in 2000 or later.
As of error you got (ORA-01858), well, fixing it depends on how exactly you're entering those values into a table.
if it was a SQL*Loader, invalid values would be rejected and stored into the .bad file and you could fix them and reprocess them later
if it was using an external tables, you could use a where clause and omit invalid rows; for example, use regexp_like
Or, your best option is to make sure that all input values are valid dates. Then any option you choose (I mentioned previously) would work without ORA-xxxxx errors.

Answer 2

Alternate way of concatenating 19 to all years, as Littlefoot suggested.
to_date(regexp_replace('13-SEP-47', '([0-9]+$)', '19\1'), 'DD-MON-YYYY')

Answer 3

I would suggest to implement the solution where 01 is not considered as 1901 but 2001 or something similar (I assume that birthday year is not 1901 for any person in your system).
Case when substr(col, -2) < to_char(sysdate,'YY')
then to_date(col, 'DD-MON-YY')
else to_date(substr(col, 1, 6) || '19' || substr(col, -2), 'dd-mm-rrrr'
End
Cheers!!