ORACLE DBA INTERVIEW QUESTIONS AND ANSWERS
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61. What is deadlock? Explain
Two processes waiting to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of this processes being killed externally.
62. What are Roles?
Roles are named groups of related privileges that are granted to users or other roles
63. What is profile?
Each database user is assigned a Profile that specifies limitations on various system resources available to the user
64. What is dynamic data replication?
Updating or Inserting records in remote database through database triggers. It may fail if remote database is having any problem
65. What is snapshot log?
It is a table that maintains a record of modifications to the master table in a snapshot. It is stored in the same database as master table and is only available for simple snapshots. It should be created before creating snapshots
66. How can we reduce the network traffic?
Replication of data in distributed environment.
Using snapshots to replicate data.
Using remote procedure calls
67. What is cluster key?
The related columns of the tables in a cluster are called the cluster key
68. What is trigger associated with the timer?
When-timer-expired
69. What is the use of image_zoom built-in?
To manipulate images in image items
70. What is logical backup?
Logical backup involves reading a set of database records and writing them into a file. Export utility is used for taking backup and Import utility is used to recover from backup
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