Oracle 11g下自动创建分区

  11g之前，维护分区需要手工。11g之后使用interval来实现自动扩展分区，简化了维护。

   根据年:  INTERVAL(NUMTOYMINTERVAL(1,'YEAR'))

   根据月:  INTERVAL(NUMTOYMINTERVAL(1,'MONTH'))

   根据天:  INTERVAL(NUMTODSINTERVAL(1,'DAY'))

   根据时分秒: NUMTODSINTERVAL( n, { 'DAY'|'HOUR'|'MINUTE'|'SECOND'})

  下面用按月自动扩展来做个试验：

SQL> create table t_range (id number not null PRIMARY KEY, test_date date)

      partition by range (test_date) interval (numtoyMinterval (1,'MONTH'))

    (

      partition p_2014_01_01 values less than (to_date('2014-01-01', 'yyyy-mm-dd'))

    );
--看到只有一个分区

SQL> select partition_name from user_tab_partitions where table_name='T_RANGE';

PARTITION_NAME

------------------------------

P_2014_01_01

SQL> insert /*+append */ into t_range  select rownum,

           to_date(to_char(sysdate - 140, 'J') +

                   trunc(dbms_random.value(0, 80)),

                   'J')

      from dual

    connect by rownum <= 100000;

SQL> commit;

--可以看到SYS开头的分区是自动扩展的

SQL> select partition_name from user_tab_partitions where table_name='T_RANGE';

PARTITION_NAME

------------------------------

P_2014_01_01

SYS_P21

SYS_P22

SYS_P23

--再看看t_range的表结构

create table T_RANGE

(

  ID        NUMBER not null,

  TEST_DATE DATE

)

partition by range (TEST_DATE)

(

  partition P_2014_01_01 values less than (TO_DATE(' 2014-01-01 00:00:00', 

  'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')),
  partition SYS_P21 values less than (TO_DATE(' 2014-02-01 00:00:00', 

  'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')),

  partition SYS_P22 values less than (TO_DATE(' 2014-03-01 00:00:00', 

  'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')),

  partition SYS_P23 values less than (TO_DATE(' 2014-04-01 00:00:00', 

  'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN'))

);

-- Create/Recreate primary, unique and foreign key constraints 

alter table T_RANGE

  add primary key (ID);

--如果对分区名不太爽，则可以自己修改一下：

alter table t_range rename partition SYS_P21 to p_2014_02_01;

alter table t_range rename partition SYS_P22 to p_2014_03_01;

alter table t_range rename partition SYS_P23 to p_2014_04_01;

自动分区的限制，摘自官方文档：

Restrictions on Interval Partitioning The 

INTERVAL

 clause is subject to the restrictions listed in "Restrictions
on Partitioning in General" and "Restrictions on Range Partitioning". The following
additional restrictions apply:

You can specify only one partitioning key column, and it must be of 

NUMBER

, 

DATE

, 

FLOAT

, or 

TIMESTAMP

 data
type.

This clause is not supported for index-organized tables.

This clause is not supported for tables containing nested table columns or varray columns.

You cannot create a domain index on an interval-partitioned table.

Interval partitioning is not supported at the subpartition level.

Serializable transactions do not work with interval partitioning. Trying to insert data into a partition of an interval partitioned table that does not yet have a segment causes an error.

In the 

VALUES

 clause:

You cannot specify 

MAXVALUE

 (an infinite upper bound), because doing so would defeat the purpose of the automatic addition of partitions as needed.

You cannot specify 

NULL

 values for the partitioning key column.