Specifying SCOPE in Parameter for BOTH, Memory & SPFILE

BOTH

Changes done immediately in SPFILE and on the running instance. Changes will remained even after database restart.

alter system set=xxx scope=both;

Memory

Change done on the running instance only. Change will lost after database restart.

alter system set=xxx scope=memory;

SPFILE

Change done on SPFILE only. Changes will affected after the database restart.

alter system set=xxx scope=spfile;