doubt on rollback segment

Hi..
I'm new to dba.i've a doubt on rollback segment..oracle guru's kindly help me..
Here'z the doubt..
Any DML statements(insert,update,delete) made to any table in the database has a rollback entry..
But even a create tablespace command(which is a DDL) updates the sys owned table 'ts$' in data dictionary. why there are no rollback entries from 'create tablespace' command.??

kindly help..

Rgds,
Sarav

who says there arent?

Hi

rollback segmenst is used when i want to read consistency..

when you create a tablespace (DDL) ----raed consistency is not requied


when you do a ddl like this...

create table xyz
as
select * from emp --------------This requires read consistancy

hence eevnthough the second is a DDL it uses rollback because the select part has to eb done in read consistent mode..

when you do such opeartion ts$..they are logged in the redologs..not the rollback..

regards
Hrishy

But pando..i've only studied that only dml statements will have rollback entries..thatz why you can rollback.
but,since ddl statements dont have a rollback entries,they cannot be rolled back.

Rgds,
sarav

well

imagine you have to alter a 100000 millions of table, alter is DDL, what happens if during your alter the databse dies? you cannot rollback but Oracle can

hey..ur answer sounds good.but can u give me a perfect answer.
tell me what happens when u give a ddl(create,alter,drop) and when you give an dml(insert,update,delete).
will there be rollback entries generated for the dml and ddl comands?

rgds,
sarav

dont know what are you talking about

Quote:

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Originally posted by ksarav
hey..ur answer sounds good.but can u give me a perfect answer.
tell me what happens when u give a ddl(create,alter,drop) and when you give an dml(insert,update,delete).
will there be rollback entries generated for the dml and ddl comands?

rgds,
sarav

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Read this...

http://asktom.oracle.com/pls/ask/f?p...2860243091362,

thanks for that article..it was really great..

thanks adewri..

rgds,
sarav