Oracle 索引数据字典、基于函数的索引

 

user_indexes 字典视图包含了索引名和唯一性，

user_ind_columns视图包含了索引名、表名、以及列名

dba_indexes dba_ind_columns 同理

select ix.table_owner,
       ic.table_name,
       ic.column_name,
       ic.index_name,
       ic.column_position,
       ix.uniqueness
  from dba_indexes ix, dba_ind_columns ic
 where ix.index_name = ic.index_name

　

　基于函数的索引

SQL> create index upper_test_table_name_idx on test(UPPER(table_name));

Index created.
当查询中使用UPPER(table_name)作为条件时，就会使用索引；否则执行全表扫描
SQL> select * from test where upper(table_name)='SDO_TXN_IDX_DELETES';

TABLE_NAME
------------------------------
SDO_TXN_IDX_DELETES
SDO_TXN_IDX_DELETES
SDO_TXN_IDX_DELETES
SDO_TXN_IDX_DELETES
SDO_TXN_IDX_DELETES

SQL>