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ORA-01450: Maximum key length exceeded - Confusion clearup needed!

From: Robert Graf-Waczenski <Office.Robert_at_waczenski.de>
Date: 10 Jun 2002 04:50:10 -0700
Message-ID: <4a1dd7f4.0206100350.16d911ce@posting.google.com>


Hi!

Our application automatically creates tables&indexes in several different databases from different vendors and on different OSes. One key issue to be solved for every database vendor is to potentially downgrade table columns to meet index length limits for the database in question.
For Oracle, we need to meet the requirements imposed by ORA-01450, ie. we have to know the maximum key length for the currently connected database.
On our platform/database (Windows 2000 / Oracle 8i / 4K block size) we have the limit of 1578 bytes.
Oracles documentation for ORA-01450 says that the actual limit is OS-dependent and that we have to look through the platform-specific documentation. This did not reveal anything... The well-know Oracle guru Thomas Kyte wrote the other day that the maximum key length is a function of the block size and that on his database with 8K block size he gets 3000-something bytes. He also writes that the limit is "a bit less then half the block size". Since Thomas is indeed a guru, i rather tend to believe him than the documentation for ORA-01450.

This leads to the final question: Does anybody know the exact definition of the limit in terms of the block size and/or other, hopefully SQL-queryable parameters? (Or, maybe, for Oracle 9i, this limit no longer applies?)

We need to know the exact limit since we have to create tables&indexes behind the scenes without skilled Oracle professionals at hand. The person running our program is not supposed to be and Oracle professional (not even a database professional...)

Any help / input is greatly appreciated!

Thx, Robert Received on Mon Jun 10 2002 - 06:50:10 CDT

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