Oracle also developed the database server Oracle, which maintains data in a highly organized manner. It lets users save and retrieve relevant data in a multi-user environment, enabling concurrent access to the same data by multiple users. It is user-friendly, has a big user community, is scalable, and is safe, making it a popular tool among Database administrators and businesses.
Oracle DBA administrators are required by companies that employ Oracle database management systems. Oracle DBAs aid firms by updating Oracle’s software, examining its security functions, and developing database storage structures. If you wish to apply for a career as an Oracle DBA, you must be prepared for the interview questions. This article contains the top 25 Oracle DBA interview questions and sample responses to help you prepare for your upcoming interview. This question includes the following:
1. In Your Opinion, Please Explain What Oracle And The Oracle Database Are.
Oracle is both a corporation and a database server with the same name. This database server manages your data in a highly organized manner, allowing users to store and retrieve data in a multiuser ecosystem. Multiple users can perform the same function of storing and retrieving data simultaneously. Oracle database refers to the software that controls the database and its actual data.
2. What Exactly Is A View?
A view is a logical table derived from one or more physical tables or views. A View is also a user-defined database object that stores the results of a SQL query for future reference.
Views do not store data physically but rather as a virtual table; hence they are also known as logical tables. The tables upon which we base views are called Base Tables, which do not contain any data.
3. What Are Your Thoughts On The Process Of Data Normalization?
Data normalization is segregating data into separate tables according to its kind. It entails constructing tables and defining their interrelationships per principles aimed at securing data while also increasing the database’s flexibility by eliminating redundancy and conflicting dependencies.
It enables developers to design more effective databases by removing duplicate data. I have utilized data normalization as part of my daily responsibilities in past positions. It is one of the most beneficial tools when working with massive data.
4. What Are The Various Oracle Database Shutdown Modes?
The four distinct types of Oracle database shutdown modes include the following:
- Transactional: No new connections are allowed, and Oracle will wait until all active processes are complete.
- Abort: This occurs immediately; however, the database is not shut down. When the database is reopened, a quick restore will be required. It is not applicable in everyday settings.
- Normal: This option prohibits new connections and terminates the database after all sessions end.
- Immediate: No new connections are allowed, and all active actions return.
5. How Would You Go About Diagnosing And Fixing A Problem With A Database?
I would first identify the root cause of the problem by evaluating its symptoms. Then, I would examine the logs and alerts for any issues that signal a potential issue. I would then execute diagnostic queries to determine the root cause of the problem. If the issue is with the application, I will contact the developer for assistance. I will restart the server and perform the query if the issue is with the database. If the error persists, I’ll examine the network connection and ensure that the user has the appropriate permissions to access the database.
6. How Can The Number Of Data Files In An Oracle Database Be Controlled?
This parameter regulates the maximum number of physical OS files that can bind to an Oracle instance. The max datafiles argument is an “absolute limit” parameter. The value supplied for max datafiles during the execution of the “new database” command is stored in Oracle control files with a default value of 32. We can use the init parameter db files to specify the maximum number of database files.
7. How Would You Describe The Oracle Grid Architecture In Your Own Words?
Oracle’s grid architecture combines a massive database server, memory, and connectivity to produce an adaptable computing resource for commercial computing needs. Grid computing design continuously analyzes resource demand and adjusts supply accordingly.
Grid computing leverages sophisticated workload management to enable programs to collaborate across multiple computers. Data processing capacity can be added or removed based on demand, and we can allocate resources flexibly.
8. Please Mention An Instance In Which You Demonstrated Technical Leadership.
In my previous position as an Oracle DBA, I was the only member of the IT department with Oracle Enterprise Manager expertise. The company employed a development intern who required access to the database but lacked the skills to use it. I spent some time demonstrating how to navigate the program and providing her with suggestions for using it more effectively. She liked the help and soon gained knowledge.
9. Describe The Distinction Between A Procedure, A Function, And A Package.
A function and a procedure are designed to be a collection of PL/SQL code that performs a single operation. A procedure is not required to return any values to the calling application, whereas a function returns a single value.
A package, on the other hand, is a grouping of operations and procedures based on their similarity to a business function or application.
10. List The Tools You Employ To Manage Your Oracle Database.
The following are some of the tools I employ when managing an Oracle database:
- Database Upgrade Assistant: This tool guides me through upgrading an existing Oracle database to a newer version.
- Oracle Net Manager: This tool guides me through the Oracle network setting.
- Oracle Enterprise Manager: I use Oracle Enterprise Manager as my primary database management tool. Once the Oracle software is installed, a database is created or upgraded, and the network is configured, I may utilize Oracle Enterprise Manager as the sole interface for controlling our database.
- The Oracle Universal Installer (OUI) installs the Oracle software and settings. It can start the Database Configuration Assistant automatically to install a database.
- Database Configuration Assistant (DBCA): The Database Configuration Assistant generates a database using Oracle-supplied templates. Additionally, we can develop our template, saving time and effort when customizing and generating a database.
11. What Exactly Is A Tablespace?
A tablespace is an Oracle database’s logical storage unit.
On the machine where the database resides, the tablespace is not visible in the file system. In turn, a tablespace consists of at least one data file that is physically placed on the server’s file system.
A data file can only belong to a single tablespace. Each table, index, etc., contained in an Oracle database is associated with a tablespace. The tablespace is the link between the Oracle database and the filesystem where the data for the table or index is kept. Oracle’s three categories of tablespaces include Permanent tablespaces, Undo tablespaces, and Temporary tablespaces.
12. What Is A Database’s Password File, And Why Is It Necessary If We Can Authenticate A User Using Data Dictionary Tables?
Data dictionary tables can authenticate database users because they contain the username and password. If a user’s password matches the one stored in the database, the user will be allowed to log in. However, this is only possible when the database is open. If the database is in shutdown mode, these tables cannot be accessible, so database administrators will utilize the password file to log in and open the database.
13. What Is The Distinction Between An Oracle Online Backup And A Cold Backup?
Offline Backup: We create an offline backup when we shut down the database with the SHUTDOWN command. Suppose the database shuts down under unknown circumstances. In that case, it should be reopened in RESTRICT mode and shut off using the NORMAL option. We should back up the corresponding files for a cold backup to be complete.
Online backup: We perform an online backup while the database is live. Some websites cannot shut down their database while creating a backup copy because they are in constant use.
14. What Exactly Is A Deadlock In Your Understanding?
Deadlock develops when two operations attempt to modify rows of a table that the other actors restrict. It is typically the result of insufficient row lock requests. A well-designed user interface program can produce this problem. As a result, the productivity of the server will decline. These restrictions will be instantly lifted when a rollback action is executed, or one of these applications is halted outside.
15. Is It Possible To Execute A SQL Query In Oracle? And What Happens If It Is Possible?
Before constructing a blueprint, it initially validates the syntax and semantics in the library’s cache. If data already exists in the buffer, it will be returned automatically to the client. Suppose the data is not in the database. In that case, it will retrieve it from the data files and store it in the database buffer cache before transmitting it to the server, which will then send it to the user.
16. What Are The Different Parts That Make Up The Logical Database Structure In The Oracle Database?
The components of Oracle database’s logical database structure are:
- Database object schemas: A schema is a collection of objects belonging to a particular user. The objects consist of tables, indexes, views, and stored procedures. In Oracle, the user represents the account, whereas the schema defines the item. On database platforms, it is also feasible to have a schema without user input.
- Tablespaces: A database primarily consists of tablespaces, which are Logical Storage Units. This tablespace is a collection of logically connected structures. Specifically, tablespace groups are associated with logical structures.
17. What Is The Distinction Between The SGA And The PGA?
System Global Space, or SGA, is the memory area defined by Oracle at instance launch. The system-level processes can share this area. On the other hand, PGA(Program Global Area) is a memory unique to a function or session. Oracle generates PGA when the Oracle process begins, and each method has its own PGA.
18. What, In Your Opinion, Is The Difference Between Differential And Incremental Backups?
Incremental backup is recognized for preserving a backup of only the modified data files since the last backup, which may have been complete or incremental. For Example, A full/incremental backup is performed at 4 p.m. on Friday, followed by another backup at 4 p.m. on Saturday. The second incremental backup will only include transactions after 4 p.m. on Friday, while the Differential backup backs up only the modified files since the last complete backup.
Suppose you perform a complete backup on Friday at 4 p.m. and a differential backup on Saturday at 4 p.m. only the files that have been modified since Friday will be backed up. In addition, if the differential backup is performed on Sunday at 4 p.m., only the files modified since Friday at 4 p.m. will be backed up.
19. What Should An Oracle Dba Do If They Observe A Decline In The Performance Of An Oracle Database?
I would first examine the existing system resources if I discovered that the performance of my Oracle database was beginning to degrade. This step will help me to determine if there were any CPU or memory use issues. If I found something correct with these resources, I would examine the network and storage systems for bottlenecks.
If I could not locate the problem, I would examine the database’s wait events and latch contention reports to see which processes create the most significant issues. I would contact the Oracle support team for assistance if I could not resolve the issue.
20. What Components Comprise A Logical Data Model?
The following components comprise a logical data model:
- Record – A record is a collection of all the attributes associated with an item for a specific condition. It is represented as a row in a table.
- Domain – A domain is the set of all possible values for a given property.
- Relationship – This object represents a relationship between two entities.
- Entity – An entity is an object type used to hold data. It includes its table.
- Attributes- This is the information about the entity we are examining. It is recorded as a column in a table with a particular data type.
21. How Frequently Do You Monitor Database Performance?
I evaluate database performance regularly, typically once per week or more frequently, depending on the project’s demands. I’ve discovered that completing routine checks enables me to detect concerns before they become serious difficulties. In my previous employment, I utilized Oracle Enterprise Manager Cloud Control 12c to monitor database performance indicators constantly. This tool assisted me in identifying database issues so I could resolve them before they become problematic.
22. What Is Your Biggest Accomplishment To Date As An Oracle DBA?
While employed by my former employer, the corporation began modifying several internal procedures. I was offered the opportunity to modify the entire organization’s database structures to accommodate their new requirements. Together with other members of my Oracle team, I worked tirelessly to ensure that the company’s database was optimized and performed efficiently before implementing the changes. Since I had just begun my career in this industry, leading the team from the beginning to the end of the project was a major accomplishment.
23. What Are The Typical Responsibilities Of An Oracle DBA?
The following are examples of frequent oracle DBA duties that I typically perform:
- Management of schema objects, including tables, indexes, and views
- Performing database backups and recovery as required
- Monitoring the health of the database and taking preventative or remedial action if needed
- Observing and adjusting performance
- Putting in Oracle software
- Establishing Oracle database
- Implementing new release-level database and software updates
- Activating and deactivating the database
- Managing the storage structures of a database
- Governance of users and security
24. What Procedure Do You Use To Back Up An Oracle Database?
RMAN is an Oracle utility that I use to do backups on both the physical and logical levels. It does this for me. Before I make a copy-only backup of all the data files, I first make a snapshot of the complete database. After that, I create a copy and backup of the previously archived redo logs. The next thing I do is create a copy-backup of the control files, and then after that, I develop a copy-backup of the parameter file. After completing these backups, I store them in distinct locations for safekeeping.
25. Do You Have Experience With Oracle Database Design?
I have experience designing Oracle databases, and I fully understand database architecture. The Oracle database consists of two primary parts: the server and client components. The server component comprises the listener, which awaits client requests. In addition, it includes a dispatcher that routes requests to the proper resource. The SQL*Net library, part of the client component, lets developers connect to the server component and send queries.
Oracle DBA interview questions is an industry-leading database management solution. Oracle is one of the most important databases in the business world, utilized by most companies. Therefore, a career in Oracle DBA is lucrative, and the employment market offers numerous options.
Practice answering the above Oracle DBA interview questions in front of a mock audience. Before attending the interview, review these questions to respond to the Oracle questions confidently. We hope you find this article helpful and can gain employment as an Oracle DBA.