分区表相关

作用:将在张大表的数据分布到多个表分区段,不同分区彼此独立,从而提高了表的可用性和性能
种类:范围分区,散列分区(使用HASH算法,最常使用),列表分区,范围/散列组合分区,范围/列表组合分区

范围分区表
创建范围分区表
create table t(v number,b number) 
partition by range(v) ( 
partition p1 values less than ('11') tablespace test1, 
partition p2 values less than ('21') tablespace test2); 

增加与删除分区
#增加分区
alter table t add partition p3 values less than ('31') tablespace test3; 
alter table t drop partition p3 

一个时间分区的例子
alter session set nls_data_lanage=AMERICAN; 
alter session set nls_data_format='DD-MON-YYYY'
create table t(v_date date,b number) 
partition by range(v_date)( 
partition p1 values less than ('01-APR-2009') tablespace test1, 
partition p2 values less than ('01-JUN-2009') tablespace test2); 

2.散列分区表(最常用)
创建
create table t1(v number,b number) 
partition by hash(v)(
partition p1 tablespace test1, 
partition p2 tablespace test2); 

增加分区
alter table t add partition p3 tablespace test3; 

删除分区
alter table t drop coalesce partition; 

3.列表分区
建列表分区
create table t(v varchar2(10),b number)
partition by list(v)(
partition p1 values('a','b') tablespace test1, 
partition p2 values('c','d') tablespace test2); 

#插入数据
SQL> insert into t values('a',10); 
SQL> insert into t values('d',20);

#注意,插入数据时第一个字段只能为a,b,c,d,否则会报错

#查询
select * from t; 
select * from t partition(p1); 
select * from t partition(p2); 
select * from t where v=XXX 

增加分区
alter table t add partition p3 values('31','32') tablespace test3; 

删除分区
alter table t drop partition p3 

4.范围/散列组合分区
建立散列组合分区
create table t(v number,b number)
partition by range(v) subpartition by hash(b)
subpartitions 2 store in (test1,test2)( 
partition p1 values less than ('11'), 
partition p2 values less than ('21')); 

查询
select * from t; 
select * from t partition(p1);

增加主分区和子分区
alter table t add partition p3 values less than ('31') tablespace test3; 
alter table t modify partition p3 add subpartition; 

删除分区
alter table t coalesce partition; 
alter table t modify partition p1 coalesce subpartition; 

5.范围/列表组合分区

创建
create table t(v number,b number) 
partition by range(v) 
subpartition by list(b) 
(partition p1 values less than ('11') tablespace test1( 
subpartition p1_1 values('1','3'), 
subpartition p1_2 values('5','6') 
), 
partition p2 values less than ('21') tablespace test2( 
subpartition p2_1 values('13','14'), 
 subpartition p2_2 values('15','16') 
)); 

查询
select * from t 
select * from t partition(p1) 
select * from t subpartition(p1_1) 
select segment_name,partition_name,tablespace_name 
from user_segments where segment_name='T'; 

增加分区和子分区
alter table t add partition p3 values less than ('31') tablespace test3( 
subpartition p3_1 values('25','26'), 
subpartition p3_2 values('22','23')); 
alter table t modify partition r3 add subpartition r3_3 tablespace test3 values('28','29'); 

删除分区
alter table t modify partition p1 coalesce subpartition; 

交换分区数据 
alter table t exchange partition p1 with table tt; 

载断分区 
alter table t truncate partition p1; 

修改分区名 
alter table t rename partition p2_1 to p2; 

合并分区 
alter table t merge partitions p1,p2 into partition p01 

重组分区 
alter table t move partition p1 tablespace test04 

为列表分区和子分区加值 
alter table t modify partition p1 add values('111'); 
alter table t modify subpartition p3_1 add values('111'); 

从列表分区和子分区中删除值 
alter table t modify partition p1 drop values('111') 
alter table t modify subpartition p3_1 drop values('111') 

分区表信息:  dba_part_tables 
显示分区:    dba_tab_partitions 
显示子分区:  dba_tab_subpartitions 
显示分区列:  dba_part_key_columns 
显示子分区列:dba_subpart_dey_columns 
显示分区索引:dba_part_indexes 
显示索引分区:dba_ind_partitions