INDEX ORGANIZED TABLES: IOT

An index organized table keeps its data sorted according to the primary key column values for the table. An Index- organized table stores entire data inthe table was stored in an index 

Index’s serve two main-purposes 

1. To enforce uniqueness, when a primary key or unique constraint is created, oracle created an index to enforce the uniqueness of the indexed columns 
2.  To improve performance when a query can use an index, the performance of the query may dramatically improve. 

Example1:

create table state_lookup_iot (

area_code number(3)

state_name varchar2(100),

city_name varchar2(100),

primary key (area_code)

)

organization index

tablespace users;

Example2:

create table customers

(

trans_id varchar2(10),

country varchar2(10),

year varchar2(10),

constraint trans_id_pk PRIMARY KEY (trans_id)

)

organization index;