Oracle创建分区索引总结
分区索引总结：
一，分区索引分为2类：
1、global，它必定是Prefix的。不存在non-prefix的
2、local，它又分成2类：
2.1、prefix：索引的第一个列等于表的分区列。
2.2、non-prefix：索引的第一个列不等于表的分区列。
LOCAL的索引只能是表的分区方式，不能自己写分区方式。他们是EQUI-Partition的。GLOBAL索引可以不分区，这个时候就是普通的一个索引。同一个列只能只有一个索引，这个列可以是GLOBAL或者是LOCAL的索引。如果唯一索引所在的列不是表的分区列，只能建立GLOBAL索引。
例如：分区表
create table test (id number,data varchar2(100))
partition by RANGE (id)
(
partition p1 values less than (10000) ,
partition p2 values less than (20000) ,
partition p3 values less than (maxvalue)
);
在ID列上创建一个LOCAL的索引
create index id_local on test(id) local;
SQL> select INDEX_NAME,PARTITION_NAME,HIGH_VALUE,STATUS from dba_ind_partitions where index_name='ID_LOCAL';
INDEX_NAME PARTITION_NAME HIGH_VALUE STATUS
------------------------------ ------------------------------ -------------------- --------
ID_LOCAL P1 10000 USABLE
ID_LOCAL P2 20000 USABLE
ID_LOCAL P3 MAXVALUE USABLE
从上面可以看出索引的分区和表一样，即是EQUI-PARTITION
如果我在表上增加个分区，则Oracle会自动维护分区的索引,注意此时加分区必须是用split,直接加会出错的。例如：
SQL> alter table test add partition p4 values less than (30000);
alter table test add partition p4 values less than (30000)
*
ERROR at line 1:
ORA-14074: partition bound must collate higher than that of the last partition
SQL> alter table test split partition p3 at (30000) into (partition p3, partition p4);
Table altered.
SQL> select INDEX_NAME,PARTITION_NAME,HIGH_VALUE,STATUS from dba_ind_partitions where index_name='ID_LOCAL';
INDEX_NAME PARTITION_NAME HIGH_VALUE STATUS
------------------------------ ------------------------------ -------------------- --------
ID_LOCAL P1 10000 USABLE
ID_LOCAL P2 20000 USABLE
ID_LOCAL P3 30000 USABLE
ID_LOCAL P4 MAXVALUE USABLE
SQL> select INDEX_NAME,INDEX_TYPE,TABLE_NAME from dba_indexes where index_name='ID_LOCAL';
INDEX_NAME INDEX_TYPE TABLE_NAME
------------------------------ --------------------------- ------------------------------
ID_LOCAL NORMAL TEST
删除id_local索引
drop index id_local;
重新在ID列上创建一个GLOBAL的索引
create index id_global on test(id) global;
SQL> select INDEX_NAME,PARTITION_NAME,HIGH_VALUE,STATUS from dba_ind_partitions where index_name='ID_GLOBAL';
no rows selected
SQL> select INDEX_NAME,INDEX_TYPE,TABLE_NAME from dba_indexes where index_name='ID_GLOBAL';
INDEX_NAME INDEX_TYPE TABLE_NAME
------------------------------ --------------------------- ------------------------------
ID_GLOBAL NORMAL TEST
从上面可以看出，它此时是个普通索引。dba_ind_partitions里根本就没有记录。
SQL>create index i_id_global on test(data) global
partition by range(id)
( partition p1 values less than (10000) ,
partition p2 values less than (MAXVALUE)
);
partition by range(id)
*
ERROR at line 2:
ORA-14038: GLOBAL partitioned index must be prefixed
此错误表示GLOBAL的索引必须是prefixed，即索引分区的列，必须是其基表的分区列。
SQL>create index id_global on test(id) global
partition by range(id)
( partition p1 values less than (10000) ,
partition p2 values less than (MAXVALUE)
);
Index created.
SQL> select INDEX_NAME,PARTITION_NAME,HIGH_VALUE,STATUS from dba_ind_partitions where index_name='ID_GLOBAL';
INDEX_NAME PARTITION_NAME HIGH_VALUE STATUS
------------------------------ ------------------------------ -------------------- --------
ID_GLOBAL P1 10000 USABLE
ID_GLOBAL P2 MAXVALUE USABLE
SQL> select INDEX_NAME,INDEX_TYPE,TABLE_NAME from dba_indexes where index_name='ID_GLOBAL';
INDEX_NAME INDEX_TYPE TABLE_NAME
------------------------------ --------------------------- ------------------------------
ID_GLOBAL NORMAL TEST
从上面可以看出，它此时是个GLOBAL的索引了。dba_ind_partitions里有记录。请和上面的做个比较，加深印象。