How to know that the database was started by spfile or pfile?

–Run the following command

SQL> show parameter spfile;

–Output

NAME  | TYPE |VALUE
——————|——————|—————————————————
spfile|string|

If the output is this(value is empty), means that oracle database was started by pfile.

NOTE :One reason oracle database was started by pfile is that it didn’t find spfile.Another is that you indicated pfile during the startup.