How to back up and restore a database in Oracle?

Backup and restore databases in Oracle can be done using the following steps:

Backup the database.

1. Performing a full database backup using the expdp tool:
   expdp system/password@SID full=y dumpfile=full_backup.dmp directory=backup_dir
2. Perform a logical backup using the exp tool: exp system/password@SID file=logical_backup.dmp full=y
3. Performing physical backups using RMAN:
   RMAN> connect to target /
   RMAN> backup the database;

Restore the database.

1. Perform a full database restore using the impdp tool:
   impdp system/password@SID full=y dumpfile=full_backup.dmp directory=backup_dir
2. Perform logical recovery using the imp tool:
   imp system/password@SID file=logical_backup.dmp full=y
3. Performing physical recovery using RMAN:
   RMAN> connect target /
   RMAN> restore database;
   RMAN> recover database;

It is important to select the appropriate backup and recovery methods based on the specific situation, while also ensuring the integrity and consistency of the data during the backup and recovery process.