Use the SET clause of the ALTER SYSTEM statement to set or change initialization parameter values. Additionally, the SCOPE clause specifies the scope of a change as described in the following table:

 Scope/Description

 SCOPE = SPFILE

The change is applied in the server parameter file only. The effect is as follows:
For dynamic parameters, the change is effective at the next startup and is persistent.
For static parameters, the behavior is the same as for dynamic parameters. This is the only SCOPE specification allowed for static parameters.

SCOPE = MEMORY

The change is applied in memory only. The effect is as follows:
For dynamic parameters, the effect is immediate, but it is not persistent because the server parameter file is not updated.

For static parameters, this specification is not allowed.

SCOPE = BOTH

The change is applied in both the server parameter file and memory. The effect is as follows:
For dynamic parameters, the effect is immediate and persistent.
For static parameters, this specification is not allowed.