increment data

bobby · Post by **bobby** » Fri Aug 13, 2004 7:40 pm

hi,
i want to incremental procedure from my sourceto staging , ahat best ways are there i know onw max timestamp but some source have no timestamp thing,plz advice.(datastage 6 have any unique feature my source and target are ora

Thanks
Bobby

chulett · Post by **chulett** » Fri Aug 13, 2004 11:12 pm

I'm going to guess what it is you are asking for.

Try searching the forum for the following terms:

CDC or the phrase "Change Data Capture"
CDD or the phrase "Change Data Detection"

Let us know if that helps...

ogmios · Post by **ogmios** » Sat Aug 14, 2004 3:43 am

In Oracle the best way to get delta's of table is to use Oracle streams (if you have a newer version of Oracle

).

In fact if you have an operational system using Oracle that can't be "stopped" for the time of the CDC extraction it's practically the only way to get correct delta's (even with timestamps on the table).

Ogmios

bobby · Post by **bobby** » Sat Aug 14, 2004 6:45 am

Hi ,
I am using oracle 8 for as source and target plugin to import data ,CDC
do we have option in oracle 8 or in datastage 6 server too.please advise if we have the option how can i find it.
Thanks,
bobby

ogmios · Post by **ogmios** » Sat Aug 14, 2004 6:50 am

It's no functionality of DataStage/Oracle itself... you write queries to fetch the differences from your source and then apply them to to the target somehow (via DataStage).

If the source was not created with CDC in mind you may be out of luck and may be have to resort to full sandboxing: do full extracts of tables and compare yourself what has changed. And unless you can stop your source system for the time of all the extracts to complete your restuls will not be 100%.

As of Oracle 9 I think you have Oracle Streams which make life easier: http://www.orafaq.com/faqstrms.htm (if you have good DBA's)

Ogmios

chulett · Post by **chulett** » Sat Aug 14, 2004 7:11 am

If CDC is not an option, then check out this post on the subject of CRC32 and CDD. It's a way to tell if something has changed without having to rely on it being "captured" for you.

bobby · Post by **bobby** » Sat Aug 14, 2004 8:08 am

Hi,
SO i guess crc32 will help in delta capture ???
Thanks,
Bobby

ogmios · Post by **ogmios** » Sat Aug 14, 2004 10:49 am

If you build it in. You would also still have to find something for deleted rows if that is a requirement for you.

Personally I would just compare columns between the original row and the new row to check for changes, but that's just me.

Ogmios