I faced few questions in few interviews even in small companies as well as big companies. 1.What is the difference between grid ,cluster and cloud? 2.Have you configured PCP?may I know the process? 3.How to reduce patching downtime? 4.What is Active Data Guard?If disk sorting happening in secondary node then will that read only database can handle that query as temp file will need to be accessed during that disk sorting operation? 5.How to configure a data Guard? 6.How to manage a snapshot database as change of state in the standby node will not hold the data? 7.Explain DRM,Cache Fusion,split brain algorithm please. 8.how to manage loss in archive gap while the database in standby node? 9.what are the types of duplication?what are the mandatory parameter need to configure during duplication? 10.Explain locks and latches 1.What is the difference between materialized view and view? 2.what is the difference between exp and expdp? 3.Can you please tell us the procedure of taking backup of a table using expdp? 4.what is your day to day activities? 5.How to know the business impact of a patch without applying the patch? 6.What is the purpose of catbundle.sql ? 7.What is the difference between generic language patches and one off patches? 8.how to upgrade opatch? 9.How do you configure autoconfig environment using tmplate? 10.How do you rebuild an index?how do you decide that an index rebuild is needed? 11.if there is no sql running in database how do you solve a performance issue? 12.If some Sql is not using an existing index what will you do?What will be possible reason behind that? 13.What are the post cloning issues have you faced? 14.How do you recover when you found blocks are corrupted?How do you able to go back to a previous incarnation? 15.11i and R12 differences? 16.what are the difference between dot tmplate file and dot drv file in each product tops?