hi,
thanks for the reply. actually i had also the knowledge that Mlog$ table is created in the case of primary key fast refresh materialized view when one creates the log on the master table.
but recently i got to hear that that mlog$ table can be created on any table and the changes in that table are stored as records in the corresponding mlo$ table.
in the net i found a definition like the following regarding creation of mlog$ table : -

CREATE TABLE "SCOTT"."MLOG$_EMP"
( "EMPNO" NUMBER(4,0),
"SNAPTIME$$" DATE,
"DMLTYPE$$" VARCHAR2(1),
"OLD_NEW$$" VARCHAR2(1),
"CHANGE_VECTOR$$" RAW(255) ) ;

so i had also created a similar table and expected to find a record when i change a record in my emp table. but that did not happen.

regards,
Prasenjit