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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Middle-Tier Inflicted Corruption
Thanks for sharing this, Ian. I forwarded it to our developers, who
sometimes try to convince me that RI should be in the application layer.
They haven't won that discussion yet, thankfully, and they are starting to
see the light :-).
We are currently developing a data collection tool to grab data from a
3rd-party PostgreSQL DB and load it into our Oracle DB. The 3rd-party has
no RI in the DB, only 1 NOT NULL in the entire DB, and uses mostly VARCHAR
datatypes (length not defined) even for *dates* (sometimes a date field has
other text in it). Needless to say, it's been challenging.
Best regards,
David B. Wagoner
Database Administrator
-----Original Message-----
From: MacGregor, Ian A. [mailto:ian_at_SLAC.Stanford.EDU]
Sent: Monday, February 02, 2004 7:27 PM
To: 'oracle-l_at_freelists.org'
Subject: Middle-Tier Inflicted Corruption
I haven't had much sleep lately. The other day someone came to ask why our Financials Peoplesoft database thought it was 1998. I checked to be sure, and the database returned the correct date. I asked them to check the client, which in this case is a Citrix farm. Some of those servers showed the 1998 dates. The maintainer of that system was queried and replied:
"The problem with the clock was due to the old domain controller not correctly synchronizing its time with the new domain controller. Which is another good reason for building a new domain controller. Because the clocks never properly synchronized, when the new domain controller came online to backup the failing primary it came up with a time that was out of date. This has caused the domain time to be out of sync. It was a last vestige of the old domain controller 'OVERLORD'. I apologize for the problems it has caused you. If you have any questions about this please let me know."
Peoplesoft (in-the-head) in their ultimate wisdom decided not to use the date on the database server, but that on the client. I now have these incorrect dates sprinkled through the system. Furthermore some have propagated from parent to child. I spent most of the weekend mining redo logs and believe I have come up with a complete list of the effected rows. One cannot ever be 100% sure. The project leaders for each Peoplesoft module have these. They will be responsible for implementing any corrections
Peoplesoft does not use database enforced referential integrity. However it does employ unique indexes and calls them primary keys. These keys can include dates. If the date of a parent table is corrected in this situation and the children are missed, those children are now orphans. If a child's record is changed and the parent's missed, same thing. If the dates are not changed then reports are incorrect. Perhaps a capital asset get's an incorrect receipt date and the depreciation schedule is thrown off.
With database enforced RI I can find the lineage of a key through all generations, but that is not so easy when it is program based.
I am open to suggestions as to how to best remedy this stituation
Ian MacGregor
Stanford Linear Accelerator Center
ian_at_SLAC.Stanford.edu
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