Hello Amar,
Using the procedure described in note 1588316 you will get one dump file per day. Files will look like this:
Database Dump: <DBSID>.DB.<DATE>.<TIME>.000
Transaction Dump: <DBSID>.TRAN.<DATE>.<TIME>.000
So, no backup will be overwritten as the timestamp will make the files unique.
I use DBACOCKPIT to schedule the dumps for the transaction log (several times a day, which results in several dump files for the transaction log), and the databases master, sybmgmtdb, saptools and <SID> (all resulting in separate files for each database).
Kindest regards, Wilbert