If I understood it correctly, when the instance is started, some views are loaded into memory and we can query against it like
v$instance. And it doesn't need db to be mounted.
If so, are there any other views which can be queried, apart from
Also, when I query
v$database, it says database is not mounted, but a different error when I try to give a random name. Is it just different error handling for the view name
v$database (as it seems to be considered something important or known database) or any other reason for this?
SQL> select * from v$database; select * from v$database * ERROR at line 1: ORA-01507: database not mounted SQL> select * from v$data; select * from v$data * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only SQL> select * from testing; select * from testing * ERROR at line 1: ORA-01219: database not open: queries allowed on fixed tables/views only
It seems the following views also work:
The reason for asking is I just want to understand the scope and purpose of each view or database table practically.