Oracle 11g虚拟列上建分区

rwedewe

在Oracle 11g上，可以在虚拟列上做分区，这个特性还比较有用，下面来做一个测试：SQL> select * from v$version;
BANNER
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Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0      Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
SQL> drop table test purge;
SQL> create table test
    (bureau_code varchar2(20) not null,
     province_code as (CAST(SUBSTR(bureau_code,0,2) AS VARCHAR2(2)))
    )
    partition by list (province_code)
    (
    partition p1 values ('01'),
    partition p2 values ('02'),
    partition p3 values ('03'),
    partition p4 values ('04'),
    partition p5 values ('05')
    );

SQL> insert into test(bureau_code) values('0101');
SQL> insert into test(bureau_code) values('0102');
SQL> insert into test(bureau_code) values('0202');
SQL> insert into test(bureau_code) values('0202');
SQL> insert into test(bureau_code) values('0302');
SQL> insert into test(bureau_code) values('0302');
SQL> insert into test(bureau_code) values('0402');
SQL> insert into test(bureau_code) values('0502');
SQL> commit;

SQL> select * from test partition(p1);
BUREAU_CODE          PR
-------------------- --
0101                 01
0102                 01

SQL> set autotrace traceonly
SQL> select * from test partition(p1);
执行计划
----------------------------------------------------------
Plan hash value: 213508695
----------------------------------------------------------------------------------------------
| Id  | Operation             | Name | Rows  | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
----------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT      |      |     2 |    30 |     4   (0)| 00:00:01 |       |       |
|   1 |  PARTITION LIST SINGLE|      |     2 |    30 |     4   (0)| 00:00:01 |    1 |     1 |
|   2 |   TABLE ACCESS FULL   | TEST |     2 |    30 |     4   (0)| 00:00:01 |    1 |     1 |--证明是走了分区的
----------------------------------------------------------------------------------------------
Note
-----
   - dynamic sampling used for this statement (level=2)
统计信息
----------------------------------------------------------
          0  recursive calls
          0  db block gets
          8  consistent gets
          0  physical reads
          0  redo size
        434  bytes sent via SQL*Net to client
        338  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          2  rows processed