Definition and backtracking of Oracle descending Index

Welcome to the Oracle community forum and interact with 2 million technical staff to access the descending order index, which is essentially the FBI. Its specific definitions can be queried through user_ind_expressions or dba_ind_expressions. Similarly, descending indexes can only be used under CBO. ConnectedtoOracle9iEnterpriseEditionRelease9

Welcome to the Oracle community forum and interact with 2 million technical staff> in descending order indexing, the FBI is essentially used. The specific definition can be queried through user_ind_expressions or dba_ind_expressions. Similarly, descending indexes can only be used under CBO. Connected to Oracle9i Enterprise Edition Release 9

Welcome to the Oracle community forum and interact with 2 million technical staff> enter

A Descending index is essentially an FBI. Its specific definitions can be queried through user_ind_expressions or dba_ind_expressions.
Similarly, descending indexes can only be used under CBO.

Connected to Oracle9i Enterprise Edition Release 9.2.0.4.0
Connected as eygle

SQL> create table t as select * from dba_users;

Table created

SQL> create index idx_username_desc on t (username desc );

Index created

SQL> select index_name, table_name, INDEX_TYPE from user_indexes where table_name =@# T @#;

INDEX_NAME TABLE_NAME INDEX_TYPE
---------------------------------------------------------------------------------------
IDX_USERNAME_DESC t function-BASED NORMAL

SQL> select column_name, column_position, descend from user_ind_columns
2 where table_name = @ # T @#;

COLUMN_NAME COLUMN_POSITION DESCEND
----------------------------------------------------
SYS_NC00013 $1 DESC

SQL>

SQL> select * from user_ind_expressions where table_name =@# T @#;

INDEX_NAME TABLE_NAME COLUMN_EXPRESSION COLUMN_POSITION
---------------------------------------------------------------------------------------------------------
IDX_USERNAME_DESC T "USERNAME" 1