Cobian Software Solutions Database Administrator DBA Interview Questions and Answers

Different types of explain plans include basic, serial, parallel, and statement-level.

• Basic explain plan shows the execution plan of a SQL statement

• Serial explain plan shows the execution plan for a serial query

• Parallel explain plan shows the execution plan for a parallel query

• Statement-level explain plan shows the execution plan for each SQL statement in a PL/SQL block

MVCC stands for Multi-Version Concurrency Control, a technique used in database management systems to allow multiple transactions to access the same data simultaneously.

• MVCC is used to maintain data consistency and prevent conflicts between transactions.

• It works by creating multiple versions of a data item, each with a timestamp indicating when it was created.

• When a transaction reads a data item, it sees the version wi...read more

Answering questions on RAC architecture, startup and shutdown process, spfile and ASM migration

• RAC architecture involves multiple nodes sharing a common storage and network infrastructure

• Startup process involves starting the Oracle Clusterware stack, starting the database instances, and mounting the database

• Shutdown process involves dismounting the database, stopping the database instances, and stopping the Oracle Clus...read more

Data Guard steps in RAC

• Configure primary and standby databases

• Enable archive log mode on primary database

• Create standby control file on standby database

• Start the Data Guard broker

• Start the redo apply process on standby database

To install SQL Server on a laptop, download the installation file from Microsoft's website and follow the installation wizard.

• Download the SQL Server installation file from Microsoft's website

• Run the installation file and follow the installation wizard

• Choose the appropriate installation options, such as the edition and features

• Set up the necessary authentication and security settings

• Complete the installation process an

Joints are used to combine data from multiple tables in a database. There are different types of joints such as inner, outer, left, and right.

• Inner join returns only the matching rows from both tables

• Outer join returns all the rows from both tables and null values for non-matching rows

• Left join returns all the rows from the left table and matching rows from the right table

• Right join returns all the rows from the right

ORA-00600 is an internal error code that indicates a software bug or corrupted data.

• ORA-00600 is a generic error message that indicates an internal error has occurred.

• It is caused by a software bug or corrupted data.

• It is a critical error that requires immediate attention from the DBA.

• The error message includes a code that identifies the specific error.

• The error can be resolved by applying a patch or contacting Oracle ...read more

ORA-600 is an internal error code in Oracle database.

• It is a generic error that indicates that something unexpected has occurred within the database.

• It is usually accompanied by a detailed error message that provides more information about the cause of the error.

• It can be caused by a variety of factors, including software bugs, hardware failures, and data corruption.

• It is important to diagnose and resolve ORA-600 error...read more

Cloning high level steps involve creating a copy of an existing database or server.

• Identify the source database or server to be cloned

• Create a backup of the source database or server

• Restore the backup to a new location or server

• Modify the cloned database or server as needed

• Test the cloned database or server to ensure it functions properly

To add a datafile in a database, use the ALTER TABLESPACE statement.

• Connect to the database as a user with the necessary privileges.

• Identify the tablespace where you want to add the datafile.

• Use the ALTER TABLESPACE statement with the ADD DATAFILE clause to add the datafile.

• Specify the file name, size, and other attributes of the datafile.

• Example: ALTER TABLESPACE users ADD DATAFILE '/path/to/datafile.dbf' SIZE 100M;

My typing speed is around 70 words per minute.

• My typing speed is measured at around 70 words per minute.

• I have experience typing for extended periods of time without fatigue.

• I am comfortable using a variety of keyboard layouts and typing software.

• I prioritize accuracy over speed when typing important documents.

• I am always looking for ways to improve my typing speed and efficiency.