Oracle case insensitive ?

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Is there a way to define Oracle database to be case insensitive?

We are looking for a way to retrieve case insensitive information from Oracle database different from using a function in where clause, e.g. WHERE Upper(kuku_id) = Upper('abc').

Regarding the best of our knowledge such functions prevent using of indexes. We have a number of requests from our customers to support case insensitive retrieve.
Example: SELECT * FROM ABC WHERE ABC_ID LIKE 'a%' should return records for both cases abc_id beginning by lowercase 'a' and abc_id beginning by UPPERCASE 'A'.
Environment: Oracle Server 7.3 for Sun Solaris Unix. Our customers have various specter of Oracle configurations from Oracle 7.0 on Novell Netware to Oracle 7.3 on HP/9000, AIS, NT and Sun Solaris. Please advise if it is a configurable option. Thanks in advance.

Leonid Borisov
Project Leader
Astea International
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BEGIN:VCARD
FN:Leonid Borisov
N:Borisov;Leonid
ORG:Astea Israel
EMAIL;INTERNET:leo_at_astea.co.il
TITLE:Project leader
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Received on Fri Feb 28 1997 - 00:00:00 CST