RE: Oracle DB migration to Postgrsql

From Oracle to <anywhere>:  

Is the treatment of empty string as NULL in Oracle different in the destination?

(And have your developers encapsulated this usefully in their applications? This can be a big deal, and can vary from application to application.)

Did you use long and or blobs of any type in Oracle, and is there an equivalent data container in the destination? There is a good chance that merely moving the data is not good enough and the developers may need to tell you application by application what they need for the migrated system to operate correctly.  

For any and all PL/SQL, is there something in the destination that can provide the equivalent?  

Constraints, enforced and not, and whether that occurs in the destination.  

Time and timestamps.  

Indexes and index types.  

Partitioning mechanics (both in general and whether unhooking older time based partitions are a nearly zero cost alternative for archive and delete).

Your developers and probably management need to be consulted about what is required for operational, policy, and legal requirements.  

For auditable manual data changes, is there a reasonable way in the destination to log everything?  

Now there is a short list. Mladen and/or others can probably be hired to help walk you through this and most folks, even brilliant ones, don’t get everything right in a first migration.  

IF you are just migrating the data to be accessed, it is less of a high wire act, but the general case of migrate USUALLY means move the data AND restore the application functionality on the destination.  

Depending on how the applications are built and packaged, a true migration can vary from a big deal to an enormous deal (and sometimes a nearly impossible deal). Developers are definitely needed. Management and applications expert users are often needed, and sometimes an enormous amount of effort can be eliminated if the exact behavior of the applications is not the goal.

Figuring this all out was in the portfolio of full service database administration circa 1985-1995. Many of today’s “DBAs” are more focused to day to day operations and possibly security. That’s not a slur, just a fact regarding the definition and common use of the term DBA then and now.  

Best wishes and good luck. I probably missed some things from this free out of my fingers short list.  

mwf  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Shravan Kumar Kota Sent: Friday, April 14, 2023 1:40 AM
To: gogala.mladen_at_gmail.com
Cc: Oracle-L Freelists
Subject: Re: Oracle DB migration to Postgrsql  

Any one can help me on this please .

On Thu, Apr 13, 2023, 08:22 Shravan Kumar Kota <shravankota_at_gmail.com> wrote:

Hello Mladen,  

Thanks you for your reply.  

I didn't understand what you are saying.  

You mean to say that we need to take help from developer while migrating database ?  

Thanks.

Shravan.

On Thu, Apr 13, 2023, 07:49 Mladen Gogala <gogala.mladen_at_gmail.com> wrote:

On 4/12/23 10:08, Shravan Kumar Kota wrote:  

Hi all ,  

Is any one done migration of Oracle database to Postgrsql?

Yes  

If yes please let me know process / steps to do it or if any doc or url please share with me.  

Thanks

Shravan.

LOL! The above message exudes a rare degree of self-confidence! The knowledge you refer to is something that I sell. However, even if if you somehow got my part of knowledge, you would still need the developer's side of the story. The developers were in charge of the application. I was only helping them with both databases. Remember: as a DBA you are a SME for everything database. The trick is in learning both.

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com





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