senior oracle dba interview questions

• What is the purpose of a password file, and why is it required? …
• What is the difference between a cluster and a grid? …
• What Is The Distinction Between Raid 5 And Raid 10? …
• What exactly is a control file? …
• What does Oracle Home Inventory entail?

In case you’re searching for Oracle DBA Interview Questions and answers for Experienced or Freshers, you are at the correct place. There is a parcel of chances from many presumed organizations on the planet. The Oracle DBA advertise is relied upon to develop to more than $5 billion by 2021, from just $180 million, as per Oracle DBA industry gauges. In this way, despite everything you have the chance to push forward in your vocation in Oracle DBA Development. Gangboard offers Advanced Oracle DBA Interview Questions and answers that assist you in splitting your Oracle DBA interview and procure dream vocation as Oracle DBA Developer.

Answering Common Oracle DBA Interview Questions

Most Frequently Asked Oracle DBA Interview Questions

Ans: Oracle Database is a relational database management system (RDBMS) which is used to store and retrieve the large amounts of data. Oracle Database had physical and logical structures. Logical structures and physical structures are separated from each other.

Ans:

Oracle DBA:

The key role of an Oracle DBA is about managing the Databases.

It contains streamlined tasks.

The working environment maintains the databases.

It works on the backend database management area.

Other tasks include Backup, recovery, server connectivity, etc.

Oracle Developer:

The key role of Oracle Developer is to develop the code.

It contains a wide range of tasks.

The working environment develops databases.

It works on the frontend development area.

Other tasks include Coding, designing UI, etc

Ans: You can get the information about the existing users in the password file querying the “v$pwfile_users” view.

Execute the SQL query below:

The query above will return four columns for each user in the password file.The column names are USERNAME,SYSDBA, SYSOPER and SYSASM.

The USERNAME column displays the username of the user in the password file

The SYSDBA column displays whether the user has SYSDBA privileges or not

The SYSOPER column displays whether the user has SYSOPER privileges or not

The SYSASM column displays whether the user has SYSASM privileges or not

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Ans: A DBA has the authority to create new users, remove the existing users, or modify any of the environment variables or privileges assigned to other users. The roles of DBA include.

Manage database storage.

Administer users and security.

Manage schema objects.

Monitor and manage database performance.

Perform backup and recovery.

Schedule and automate jobs.

Ans: The following tasks are carried out by Oracle DBA.

Installing Oracle software.

Creating Oracle databases.

Performing upgrades of the database and software to a new release level.

Starting up and shutting down the database.

Managing the database’s storage structures.

Managing users and security.

Managing schema objects, such as tables, indexes, and views.

Making database backups and performing recovery when necessary.

Proactively monitoring the database’s health and taking preventive or corrective actions as required.

Monitoring and tuning performance.

Ans: The various Oracle database objects are:

Ans: Every Oracle database has a control file. A control file is a small binary file that records the physical structure of the database and includes:

The database name.

Names and locations of associated datafiles and online redo log files.

The timestamp of the database creation.

The current log sequence number.

Checkpoint information.

Ans: The following tools are the products, tools and utilities used for administering the database.

Oracle Universal Installer(OUI).

Database Configuration Assistant(DBCA).

Database Upgrade assistant.

Oracle Net Manager.

Oracle Enterprise Manager.

Ans: The following are the dictionary tables used in monitoring a databases space.

Ans:

Enterprise Backup Utility (EBU) is a functionally rich, high-performance interface for backing up Oracle7 databases. It is sometimes referred to as OEBU for Oracle Enterprise Backup Utility.

The Oracle Recovery Manager (RMAN) utility that ships with Oracle8 and above is similar to Oracle7s EBU utility. However, there is no direct upgrade path from EBU to RMAN.

Ans: Following is the logical structure of the disk resources:

Data block: The data block refers to the smallest logical storage unit. Size of a data block is a multiple of the operating system block size.

Extent: It refers to the contiguous set of data blocks, which is allocated as a unit to a segment.

Tablespace: The tablespace refers to the final logical storage unit. It is mapped to the physical datafile.

Segment: The segment allocates a logical structure, such as a table. It is a set of extents, which are stored in the same tablespace.

Ans: You can use the following database views to get the information on database size:

Dba_segments: It provides information about the used space. You can take a total of all the bytes in the dba_segments view to get the used space.

Dba_data__files: It provides information on space allocated to datafiles for permanent tablespaces.

v$log: It provides information on redo log files.

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Ans: There are three different levels of auditing.

Statement Auditing: It allows you to track who is issuing a specific type of statements. The AUDIT statement form of the AUDIT command allows you to specify any SQL statement to be audited.

Privilege Auditing: It lets you track the use of system privileges. In the AUDIT command, you can specify any system privilege. An audit record will be generated any time you exercise the specified system privilege.

Object Auditing: It is the auditing of accesses to specific schema objects without regard to the user. It can audit all SELECT and DML statements permitted by object privileges, such as SELECT or DELETE statements on a particular table.

Ans: The performance tuning field cant be automated like other features of exp/imp, backup recovery.This is an area that requires more detective work to be carried on part of application programmers and DBAs to check how some process is running slower than expected, why cant we scale applications to a larger number of users without problems like performance degradation etc. This is an area where the technical knowledge must be used along with constant experimentation and observation.

Ans:

Dynamic performance views are also called V$ views. These views provide information about the sessions.

Any Oracle user can get information from dynamic performance views if the user has to select any table privilege. This privilege is generally granted through the SELECT_CATALOG_ROLE role.

Ans: It is an instance that manages ASM disk groups. It comprises the System Global Area(SGA) and background processes. ASM instance mounts a disk group that is made available to the database instance. An ASM instance manages the metadata of a disk group and provides file layout information to the database instances.

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Ans: It is a group of disks that ASM manages as a unit. Within the disk groups, a file system interface maintains the Oracle database files. ASM simplifies database storage by consolidating disks into disk groups. This reduces I/O overhead.

Ans: Following is the procedure of restoring RMAN for the recovery:

Bring all the nodes down.

Start a node.

Restore all the data files and archive logs.

Recover the node.

Open the database.

Bring other nodes up.

Confirm that all nodes are operational.

Ans:

Instance recovery is used in Real Application Cluster (RAC) environments only.

It occurs in an open database when one instance detects that another instance has crashed.

Ans: The following files must be backed up.

Database files.

Control files.

Archived log files.

Password files.

INIT.ORA.

Ans:

A backup set is a logical grouping of backup files that are created when you issue an RMAN backup command.

It is RMANs name for a collection of files associated with a backup. A backup set is composed of one or more backup pieces.

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Ans: Following are the architectural components of RMAN:

RMAN executable.

Server processes.

Channels.

Target database.

Recovery catalog database.

Media management layer.

Backups, backup sets and backup pieces.

Ans:

RMAN backup consists of a backup of all or part of a database.

This results from issuing an RMAN backup command.

A backup consists of one or more backup sets.

Ans: A recovery catalogue is a database plan that holds the metadata used by RMAN for reinstallation and healing processes. It stores information on

Data files & their backup file.

Incarnation.

Stored scripts.

Backup history.

Archived Redo Logs & their backup sets.

Ans:

1) The database resource manager enables us to limit the length of time a user session can stay idle and to automatically terminate long-running SQL statements and user sessions.

2) We can set initial login priorities for various consumer groups by using the database resource manager.

3) We can specify the maximum number of concurrent active sessions for a consumer group by using the concept of active session pool. The Database resource manager will automatically queue all the subsequent requests until the currently running sessions complete.

Ans: The resource plan lays how resource consumer groups will allocate the resources. Each resource plan contains a set of resource consumer groups that belong to this plan, together with instructions as to how resources are to be allocated among these groups.

For instance, a resource plan may dictate CPU resources be allocated among three resource consumer groups so that the first group gets 60 per cent and the remaining two groups get 20 per cent each of the total CPU time.

Ans:

Database Instances and Automatic Storage Management (ASM): Database instances and ASM instances will be restarted if they crash somehow.

Oracle NET Listener: Oracle NET Listener will be started if it crashes and stops listening for an incoming connection.

ASM Disk Groups: Oracle Restart will mount ASM Disk groups if they are dismounted.

Database Services: Non-default database services will be started by Oracle Restart feature.

Oracle Notification Services (ONS): This is another Oracle component that can be protected by Oracle Restart.

Ans: You can start up a database with three tools.

SQL*Plus: This is the most widely used option. You first connect to an idle instance with SQL*Plus and then startup the instance with the “startup” command.

Oracle Enterprise Manager: This is another way of starting up a database. You can logon to Oracle Enterprise Manager even if the database is stopped. OEM will detect the status of the down database and will present you with a “Startup” button. You can startup the database by clicking this button.

RMAN: This is rather a less used tool for starting up a database but it is possible to startup a database from the Recovery Manager command line.

Ans:

Controlling access to data(authorization).

Restricting access to legitimate users (authentication).

Ensuring accountability on part of the users(auditing).

Safeguarding key data in the database(encryption).

Managing the security of the entire organizational information structure (enterprise security).

Ans: You can use direct path load to improve the performance. Indexes and constraints make inserts slow. Removing indexes and constraints improve performance of inserts; and therefore, of SQL*Loader.

In case you’re searching for Oracle DBA Interview Questions and answers for Experienced or Freshers, you are at the correct place. There is a parcel of chances from many presumed organizations on the planet. The Oracle DBA advertise is relied upon to develop to more than $5 billion by 2021, from just $180 million, as per Oracle DBA industry gauges. In this way, despite everything you have the chance to push forward in your vocation in Oracle DBA Development. Gangboard offers Advanced Oracle DBA Interview Questions and answers that assist you in splitting your Oracle DBA interview and procure dream vocation as Oracle DBA Developer.

Answer: An information square is the littlest unit of intelligent stockpiling for a database object. As items develop they take pieces of extra stockpiling that are made out of touching information squares. These groupings of coterminous information squares are called degrees. Every one of the degrees that an article takes when gathered are viewed as the portion of the database object.

Answer: Ordinary: In this mode, no new associations are permitted and the database is shut after every one of the sessions detaches themselves. Quick: No new associations are permitted and the current dynamic exchanges are moved back. Changes made by a functioning exchange are lost in this alternative. Value-based: No new associations are permitted and Oracle holds up until every single dynamic exchange are finished. Prematurely end: This happens quickly, notwithstanding, the database isnt closed down neatly. The database should perform case recuperation next time it is begun. This choice ought not be utilized in standard exercises.

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Answer: The items accordingly can be put away in the database. The language of the DBMS can be coordinated with an item arranged programming language. The language may even be equivalent to that utilized in the application, which does not constrain the software engineer to have two portrayals of his items.

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Criteria	Oracle DBA Characteristics
Main storage structures	Logical and physical
Architecture	Grid architecture
ACID Compliance	Fully compliant
Data stored as	Data blocks, extents, segments, and tablespaces

FAQ

What are the roles and responsibilities of Oracle DBA?

• Mention Oracle DBA Characteristics. …
• What is Oracle? …
• What is an Oracle Database? …
• What is an Oracle index? …
• Why is the index used? …
• Who is responsible to update the indexes? …
• What are the various databases available in the market?

Is Oracle DBA a good career?

• Installing Oracle software.
• Creating Oracle databases.
• Performing upgrades of the database and software to new release levels.
• Starting up and shutting down the database.
• Managing the database’s storage structures.
• Managing users and security.

What is SCN and checkpoint in Oracle?