Wistron Oracle Database Administrator Interview Questions, Process, and Tips

Recovering deleted datafiles without backup

• Check if the datafiles are still in the operating system's recycle bin or trash folder

• Use data recovery software to scan the hard drive for deleted files

• If the above methods fail, try to recreate the datafiles using the CREATE DATAFILE command

• If the tablespace is still intact, use the RMAN RECOVER TABLESPACE command to recover the data

To check DR DC sync, use Data Guard Broker or query V$DATAGUARD_STATS view.

• Use Data Guard Broker to check the status of the standby database and its synchronization with the primary database.

• Query V$DATAGUARD_STATS view to check the redo apply lag and transport lag between the primary and standby databases.

• Check the alert log files of both primary and standby databases for any errors or warnings related to data synchro

ER diagrams are visual representations of entities and their relationships in a database.

• ER stands for Entity-Relationship

• ER diagrams are used to design and model databases

• Entities are represented as rectangles, relationships as diamonds, and attributes as ovals

• Examples of entities include customers, orders, and products

• Examples of relationships include one-to-one, one-to-many, and many-to-many

Cold backup is taken when the database is offline while hot backup is taken when the database is online.

• Cold backup is taken when the database is shut down and all files are copied to a backup location.

• Hot backup is taken while the database is still running and all files are copied to a backup location.

• Cold backup is slower and requires downtime while hot backup is faster and does not require downtime.

• Cold backup is mo...read more

To connect to RMAN, use the 'rman' command in the command prompt or terminal.

• Open the command prompt or terminal

• Type 'rman' and press enter

• Enter the username and password for the target database

• Use the 'connect' command to connect to the target database

• Use the 'run' command to execute RMAN commands