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copied!<p>Case sensitivity is fundamental to computing, for the simple reason that the ASCII value of 'yun' != the ASCII value of 'YUN'. So, when you say ... </p> <blockquote> <p>consider data as case insensitive</p> </blockquote> <p>... do you mean just for the purposes of search or for storage as well?</p> <p>The problem with enforcing case on every search is this:</p> <pre><code>SQL> create table t23 (id number, name varchar2(20)) 2 / Table created. SQL> create unique index t23_uk on t23(name) 2 / Index created. SQL> insert into t23 values (1, 'SAM-I-AM') 2 / 1 row created. SQL> insert into t23 values (2, 'sam-i-am') 2 / 1 row created. SQL> select id, name, ascii(name) from t23 2 / ID NAME ASCII(NAME) ---------- -------------------- ----------- 1 SAM-I-AM 83 2 sam-i-am 115 SQL> </code></pre> <p>If case insensitive searches are enforced at the schema or table level how can we ever distinguish 'sam-I-am' from 'SAM-I-AM'? </p> <p>It is - sort of - possible to enforce case-insensitivity for data storage, albeit at the individual column level:</p> <pre><code>SQL> delete from t23 2 / 2 rows deleted. SQL> drop index t23_uk 2 / Index dropped. SQL> create unique index t23_uk on t23(upper(name)) 2 / Index created. SQL> insert into t23 values (1, 'SAM-I-AM') 2 / 1 row created. SQL> insert into t23 values (2, 'sam-i-am') 2 / insert into t23 values (2, 'sam-i-am') * ERROR at line 1: ORA-00001: unique constraint (APC.T23_UK) violated SQL> </code></pre>

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