Oracle V$ views

v$controlfile: Displays the location and status of each controlfile in the database. 

Column	Datatype	Description
STATUS	VARCHAR2(7)	INVALID if the name cannot be determined, which should not occur. Null if the name can be determined.
NAME	VARCHAR2(513)	Name of the control file
IS_RECOVERY_DEST_FILE	VARCHAR2(3)	Indicates whether the file was created in the flash recovery area (YES) or not (NO)

v$Database: Displays information about the database from the control file.

For example, you can check (using log_mode) whether or not the database is in archivelog mode:

SQL>select log_mode from v$database;

LOG_MODE
------------
ARCHIVELOG

checkpoint_change# records the SCN of the last checkpoint.

switchover_status: can be used to determine if it is possible to perform a switchover operation Only available for physical standby databases. Can be:

• NOT ALLOWED,
• SESSIONS ACTIVE,
• SWITCHOVER PENDING,
• SWITCHOVER LATENT,
• TO PRIMARY,
• TO STANDBY or
• RECOVERY NEEDED.

See protection modes in data guard for the columns protection_mode and protection_level.

database_role determines if a database is a primary or a logical standby database or a physical standby database.

force_logging tells if a database is in force logging mode or not.