29 Jul 09 13:46
The docs indicate that Oracle sees an index with ASC or DESC as Function-based - as such, there is probably no dictionary entry specifying the order (The function itself handles this, not a dictionary entry )
ASC | DESC
Use ASC or DESC to indicate whether the index should be created in ascending or descending order. Indexes on character data are created in ascending or descending order of the character values in the database character set.
Oracle treats descending indexes as if they were function-based indexes. You do not need the QUERY REWRITE or GLOBAL QUERY REWRITE privileges to create them, as you do with other function-based indexes. However, as with other function-based indexes, Oracle does not use descending indexes until you first analyze the index and the table on which the index is defined. See the column_expression clause of this statement.
Restriction: You cannot specify either of these clauses for a domain index. You cannot specify DESC for a reverse index. Oracle ignores DESC if index is bitmapped or if the COMPATIBLE initialization parameter is set to a value less than 8.1.0.
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