–Have higher availability because table reorganization does not invalidate secondary indexes
索引组织表的限制条件：必须有主键约束且不能延迟，不能是簇表，不能被复合分区，不能包含rowid和long型的字段类型
–Must have a primary key that is not DEFERRABLE
–Cannot be clustered
–Cannot use composite partitioning
–Cannot contain a column of type ROWID or LONG
SQL> CREATE TABLE "HR"."IOT" ( "A" NUMBER, "B" DATE, PRIMARY KEY ("A") VALIDATE ) ORGANIZATION INDEX;
Table created.
SQL> select object_name,object_id from dba_objects o where o.owner='HR' and o.object_name='IOT';
OBJECT_NAM OBJECT_ID
---------- ----------
IOT 68596
三：簇表，即两张表公共存储在同一个区上，join查询的速度较快
簇表分索引簇，哈希簇，排序哈希簇
SQL> create cluster cluster1 (a number) index;
Cluster created.
SQL> create table c1 (a number,b varchar2(20)) cluster cluster1(a);able created
Table created
SQL> create table c2 (a number,b date) cluster cluster1(a);
Table created
SQL> create cluster cluster2 (a number) hashkeys 3;
Cluster created.
SQL> create cluster cluster3 (a number,b number sort) hashkeys 3;
Cluster created
四：预估表大小和增长趋势
本文出自 “月牙天冲” 博客