分区表：range分区，list分区，hash分区

分区表：range分区，list分区，hash分区

(1)分区表包含多个分区，每个分区都是在一个独立的segment上面，可以存放不同的表空间；
--(1.1)官方推荐超过2G的表，需要分区表；
--(1.2)表中含有历史数据，新的数据添加到最新的分区；例如11个月的数据只是读，最新1个月的数据为修改；需要用分区表；
--(1.3)oracle 10g支持1024K-1个分区；
--(2)分区表的优点
--2.1 可以对单独的分区进行备份和恢复
--2.2 分散IO
--(3)oracle 10g支持的分区
--范围分区range
--哈希分区hash
--列表分区list
--范围哈希复合分区range-hash
--范围列表复合分区range-list
--(4)range分区

create table rangetable(id number(9),time d ate) partition by range(time)
(
partition p1 values less than (to_date('2010-2-1','yyyy-mm-dd') ),
partition p2 values less than (to_date('2010-3-1','yyyy-mm-dd') ),
partition p3 values less than (to_date('2010-4-1','yyyy-mm-dd') ),
partition p4 values less than(maxvalue)
);

--查看分区表的基本信息
select * from user_part_tables;
select table_name,partitioning_type,partition_count
from user_part_tables where table_name='RANGETABLE';
--查看表的分区信息:分区名称，默认的extents个数
select * from user_tab_partitions where table_name='RANGETABLE';
select table_name,high_value,partition_name from user_tab_partitions
--拆分分区表：拆分maxvale/default分区表；
alter table rangetable split partition p4 at(to_date('2010-5-1','yyyy-mm-dd'))
into (partition p5,partition p6)
alter table rangetable split partition p6 at(to_date('2010-7-1','yyyy-mm-dd'))
into (partition p6,partition p7)
--插入数据
insert into rangetable values(1,to_date('2010-01-01','yyyy-mm-dd'));
insert into rangetable values(1,to_date('2010-02-01','yyyy-mm-dd'));
insert into rangetable values(3,to_date('2010-03-01','yyyy-mm-dd'));
select * from rangetable;
--统计segments
select partition_name,count(*) from user_extents where segment_name='RANGETABLE' group by partition_name;
--(5)list分区
--list分区必须制定列值，列植必须明确；要创建default分区来存储不明确的值；
create table listtable
(
id number(10) not null,
areacode varchar2(20)

)
partition by list(areacode)
(
partition list_025 values('025'),
partition list_035 values('035'),
partition list_045 values('045'),
partition list_055 values('055'),
partition list_other values (default)
)
--插入数据
insert into listtable values(1,'025');
insert into listtable values(2,'035');
insert into listtable values(3,'045');
insert into listtable values(4,'055');
insert into listtable values(5,'075');
--查看分区信息
select * from user_part_tables;
select * from listtable;
select * from user_tab_partitions where table_name='LISTTABLE';
--统计segments
select partition_name,count(*) from user_extents where segment_name='LISTTABLE' group by partition_name;
--(6)hash分区
create table hashtable
(
id number(9),
areacode varchar2(10)
)
partition by hash(areacode)
partitions 5;
--插入数据
insert into hashtable values(1,'025');
insert into hashtable values(2,'035');
insert into hashtable values(3,'045');
insert into hashtable values(4,'055');
insert into hashtable values(5,'075');
commit;
--统计segments
select partition_name,count(*) from user_extents where segment_name='HASHTABLE' group by partition_name;
select * from dba_extents where segment_name='HASHTABLE';