Question

there is no possibility to store one data files in to two table space.but when creating IOT in oracle we are giving over flow property to another table space!
usually data file contains tables even IOT see this image Click for concept here!so how can point out two tablespace for pointing one table(IOT).
let is consider the following code:

CREATE TABLE admin_docindex(
        token char(20), 
        doc_id NUMBER,
        token_frequency NUMBER,
        token_offsets VARCHAR2(2000),
        CONSTRAINT pk_admin_docindex PRIMARY KEY (token, doc_id))
    ORGANIZATION INDEX 
    TABLESPACE admin_tbs
    PCTTHRESHOLD 20
    OVERFLOW TABLESPACE admin_tbs2;

Answer 1

One segment in Oracle will be stored in exactly one tablespace. But one object may be comprised of many different segments. For example, if you have a partitioned table, each partition is a separate segment each of which may be stored in a different tablespace. Each LOB in a table is a separate segment that can potentially be stored in a different tablespace. And, in your case, the row overflow area is a separate segment from the segment storing the main table segment.

The various scenarios where a table can comprise multiple segments was discussed over on the DBA stack yesterday.