Cada database Oracle tem I. um ou mais datafiles. II. um control fil...

All of the statements (I, II, and III) are correct regarding the components of an Oracle database.

I. Datafiles: An Oracle database is made up of one or more datafiles. These datafiles store the actual data and the metadata for the database. You can view them with the following SQL statement: SELECT file_name, tablespace_name, bytes/1024/1024 AS size_mb
FROM dba_data_files;


II. Control File: The control file is a critical component of an Oracle database. It contains metadata about the database, such as the database name, the names and locations of datafiles and redo log files, timestamp information, and the database's current log sequence number. You can query the v$controlfile to view it:
SELECT name FROM v$controlfile;


III. Redo Log Files: The redo log is a set of files that record changes made to the database. It is crucial for database recovery in the event of a failure. The redo log files store a log of all changes made to the database, which can be used to reconstruct the database in the case of a crash. To see this information you can query the log view: SELECT group#, thread#, sequence#, members, status, first_change#,
first_time, next_change#, next_time
FROM v$log;