Oracle 数据表之分区表
一、分区方法
建分区表准备:
1,创建4个测试用的表空间,每个表空间作为一个独立分区(考虑到Oracle中分区映射的实现方式,建议将表中的分区数设置为2的乘方,以便使数据均匀分布)
create tablespace partition1 datafile ‘/home/oracle/app/oradata/orcl/partition1.dbf‘ size 20m;
create tablespace partition2 datafile ‘/home/oracle/app/oradata/orcl/partition2.dbf‘ size 20m;
create tablespace partition3 datafile ‘/home/oracle/app/oradata/orcl/partition3.dbf‘ size 20m;
create tablespace partition4 datafile ‘/home/oracle/app/oradata/orcl/partition4.dbf‘ size 20m;
1)范围分区
范围分区就是对数据表中的某个值的范围进行分区,根据某个值的范围,决定将该数据存储在哪个分区上。如根据序号分区,根据业务记录的创建日期进行分区等(联通每个月的账单记录就用的分区表存储)。
CREATE TABLE partition_table(
kind_id number ,
id number not null,
name varchar(100),
start_date date not null
)
partition by range(kind_id) (
partition partition1 values less than(2) tablespace partition1,
partition partition2 values less than(4) tablespace partition2,
partition partition3 values less than(6) tablespace partition3,
partition partition4 values less than(maxvalue) tablespace partition4
)
插入数据
insert into partition_table values(1,1001,‘haha‘,to_date(‘2012‘,‘yyyy‘));
insert into partition_table values(2,1002,‘sasa‘,to_date(‘2013‘,‘yyyy‘));
insert into partition_table values(3,1003,‘dada‘,to_date(‘2014‘,‘yyyy‘));
insert into partition_table values(4,1004,‘faga‘, to_date(‘2015‘,‘yyyy‘));
insert into partition_table values(5,1005,‘gaga‘,to_date(‘2016‘,‘yyyy‘));
insert into partition_table values(6,1006,‘jaja1‘,to_date(‘2017‘,‘yyyy‘));
insert into partition_table values(8,1007,‘kaka‘,to_date(‘2018‘,‘yyyy‘));
查询数据:
不指定分区:
select * from partition_table
指定分区:
select * from partition_table partition(partition1)
更改数据:
指定分区:
update partition_table partition(partition1) t set t.name = ‘kkkl‘ where start_date <to_date(‘2015‘);
不指定分区
update partition_table t set t.name = ‘kkkl‘ where t.start_date <to_date(‘2015‘);
3)散列分区(hash分区)
create table hash_partition_table(
kind_id number ,
id number not null,
name varchar(100),
start_date date not null
)
partition by hash(kind_id)(
partition partition1 tablespace partition1;
partition partition2 tablespace partition2;
partition partition3 tablespace partition3;
partition partition4 tablespace partition4;
)
4)复合分区(子分区)
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