24 Oracle 19c Interview Questions and Answers

Introduction:

Are you preparing for an Oracle 19c interview? Whether you are an experienced professional or a fresher, it's essential to be well-prepared for common questions that may be asked during the interview. In this blog, we will cover 24 Oracle 19c interview questions and provide detailed answers to help you ace your interview.

Role and Responsibility of an Oracle 19c Database Administrator:

An Oracle 19c Database Administrator (DBA) plays a crucial role in managing and maintaining Oracle databases. Their responsibilities include installing, configuring, and upgrading database software, monitoring database performance, ensuring data security, and handling backup and recovery processes.

Common Interview Question Answers Section:

1. What is Oracle 19c?

The interviewer wants to assess your basic knowledge of Oracle 19c, the specific version of the Oracle Database.

How to answer: Oracle 19c is the latest long-term support release of the Oracle Database. It comes with various new features and improvements in performance, security, and manageability.

Example Answer: "Oracle 19c is the latest version of the Oracle Database, known for its enhanced performance and security features. It's the long-term support release, ensuring stability for businesses."

2. What are the key features of Oracle 19c?

The interviewer is interested in your understanding of the standout features in Oracle 19c.

How to answer: Highlight features such as Automatic Indexing, Real Application Clusters (RAC) improvements, and enhanced security options like Data Redaction.

Example Answer: "Oracle 19c introduces several key features, including Automatic Indexing for improved performance, enhancements to Real Application Clusters for high availability, and advanced security features like Data Redaction."

3. Explain what a PDB is in Oracle 19c.

The interviewer wants to know if you are familiar with Pluggable Databases (PDBs) in Oracle 19c.

How to answer: Explain that PDBs are a container within a Multitenant Database (CDB) and can be plugged into or unplugged from a CDB. They allow for easier management and resource allocation for multiple databases.

Example Answer: "A PDB, or Pluggable Database, is a container within an Oracle Multitenant Database (CDB). It allows multiple databases to share resources and can be plugged into or unplugged from the CDB, making database management more flexible and efficient."

4. What is Automatic Indexing in Oracle 19c?

The interviewer is interested in your knowledge of Automatic Indexing, a new feature in Oracle 19c.

How to answer: Explain that Automatic Indexing is a self-tuning feature that automates the creation, maintenance, and optimization of database indexes based on usage patterns and query performance.

Example Answer: "Automatic Indexing in Oracle 19c is a revolutionary feature that uses machine learning to create and maintain indexes. It continuously evaluates query performance and automatically creates or drops indexes to improve database performance."

5. What are the benefits of Real Application Clusters (RAC) in Oracle 19c?

The interviewer wants to know about the advantages of using Real Application Clusters in Oracle 19c.

How to answer: Highlight the high availability, scalability, and load balancing capabilities provided by RAC, allowing multiple nodes to work together in a cluster.

Example Answer: "Real Application Clusters in Oracle 19c offer increased availability by allowing multiple nodes to work together. They also provide scalability and load balancing, ensuring optimal performance even during high workloads."

6. What is Data Redaction in Oracle 19c, and why is it important?

The interviewer is interested in your understanding of data security features in Oracle 19c.

How to answer: Explain that Data Redaction is a security feature that allows you to redact sensitive data before it is displayed to users. It is essential for protecting sensitive information in applications and meeting compliance requirements.

Example Answer: "Data Redaction in Oracle 19c is a crucial security feature. It automatically masks or redacts sensitive data before it's presented to users. This helps protect sensitive information and ensures compliance with data privacy regulations."

7. What is Multitenant Architecture in Oracle 19c, and how does it differ from non-CDB databases?

The interviewer wants to assess your knowledge of Oracle 19c's Multitenant architecture and its advantages.

How to answer: Explain that Multitenant Architecture allows multiple Pluggable Databases (PDBs) to share a single Container Database (CDB). It is more efficient than traditional non-CDB databases in terms of resource utilization and management.

Example Answer: "The Multitenant Architecture in Oracle 19c allows multiple PDBs to share a single CDB, which is more efficient than traditional non-CDB databases. It simplifies database management, reduces resource overhead, and provides a more consolidated approach to database administration."

8. What is Oracle ASM, and how does it benefit database storage in Oracle 19c?

The interviewer is interested in your understanding of Oracle ASM (Automatic Storage Management) and its role in Oracle 19c.

How to answer: Explain that Oracle ASM is a disk management solution that simplifies the storage of Oracle database files. It provides benefits such as performance optimization, redundancy, and ease of management.

Example Answer: "Oracle ASM is an integral part of Oracle 19c, simplifying database storage. It optimizes disk performance, ensures data redundancy, and eases the management of database files, making it a valuable addition to Oracle 19c."

9. What is a SQL Plan Baseline in Oracle 19c, and why is it important?

The interviewer wants to assess your knowledge of SQL Plan Baselines in Oracle 19c and their significance.

How to answer: Explain that SQL Plan Baselines are a way to lock in known, optimal execution plans for SQL statements, ensuring consistent performance and reducing the risk of suboptimal plan changes.

Example Answer: "SQL Plan Baselines in Oracle 19c are crucial for maintaining consistent query performance. They capture and preserve known good execution plans, preventing suboptimal plan changes that can affect database performance."

10. What is the Oracle Database Architecture in Oracle 19c?

The interviewer wants to gauge your knowledge of the fundamental architecture of Oracle Databases.

How to answer: Explain the key components of the Oracle Database Architecture, including the instance and data files, memory structures, and background processes.

Example Answer: "The Oracle Database Architecture in Oracle 19c comprises the instance (SGA and background processes) and data files (tables, indexes). Memory structures like the SGA and PGA are used for caching and processing data, while background processes handle various tasks, such as recovery and data consistency."

11. What is the importance of the UNDO tablespace in Oracle 19c?

The interviewer is interested in your understanding of the UNDO tablespace and its role in Oracle 19c.

How to answer: Explain that the UNDO tablespace is critical for managing transactions, providing a mechanism to roll back changes and ensure data consistency in case of rollbacks or crashes.

Example Answer: "The UNDO tablespace in Oracle 19c is vital for transaction management. It stores 'undo' information, allowing us to roll back changes and maintain data consistency. In the event of rollbacks or system crashes, the UNDO tablespace is crucial for data integrity."

12. Explain the concept of Database Redo Logs in Oracle 19c.

The interviewer wants to assess your knowledge of Database Redo Logs and their significance in Oracle 19c.

How to answer: Describe that Database Redo Logs record changes made to the database, providing a crucial mechanism for data recovery, backup, and ensuring transaction durability.

Example Answer: "Database Redo Logs in Oracle 19c are critical for data recovery and backup. They record all changes made to the database and play a vital role in ensuring transaction durability and maintaining a consistent state of the database."

13. What are Oracle Database Constraints, and how are they used?

The interviewer is interested in your knowledge of constraints in Oracle Databases and their purpose.

How to answer: Explain that constraints are rules applied to columns to maintain data integrity. They ensure data accuracy and consistency within the database.

Example Answer: "Oracle Database Constraints are rules applied to columns, ensuring data integrity. They include Primary Key, Foreign Key, Unique, Check, and Not Null constraints. Constraints help maintain data accuracy and consistency by enforcing rules on data values."

14. What is the purpose of the Oracle Data Dictionary in Oracle 19c?

The interviewer wants to assess your understanding of the Oracle Data Dictionary and its importance.

How to answer: Explain that the Oracle Data Dictionary is a set of metadata tables that store information about the database's structure and objects. It plays a crucial role in database management and query optimization.

Example Answer: "The Oracle Data Dictionary in Oracle 19c is a collection of metadata tables that store information about the database's structure and objects. It is essential for database management, query optimization, and understanding the database's structure."

15. What is the difference between a Full Database Export and a Data Pump Export in Oracle 19c?

The interviewer wants to know the distinctions between different types of database exports in Oracle 19c.

How to answer: Explain that a Full Database Export exports the entire database, including data and metadata, while a Data Pump Export is more flexible, allowing for selective export of specific objects or schemas.

Example Answer: "A Full Database Export in Oracle 19c exports the entire database, including data and metadata. On the other hand, a Data Pump Export offers more flexibility, allowing us to choose specific objects or schemas to export, making it suitable for selective backups and migrations."

16. What is Oracle RMAN, and how does it benefit database backup and recovery?

The interviewer is interested in your knowledge of Oracle Recovery Manager (RMAN) and its role in Oracle 19c.

How to answer: Explain that Oracle RMAN is a tool for backing up and recovering Oracle databases. It simplifies backup processes, supports incremental backups, and ensures data recovery in case of failures.

Example Answer: "Oracle RMAN is a powerful tool for managing database backups and recoveries. It streamlines the backup process, supports incremental backups, and provides a reliable mechanism for restoring data in the event of failures, ensuring data availability and integrity."

17. What is the purpose of the Oracle Flashback Technology in Oracle 19c?

The interviewer wants to assess your understanding of Oracle Flashback Technology and its significance in Oracle 19c.

How to answer: Explain that Oracle Flashback Technology allows you to view and recover past database states without using traditional point-in-time recovery methods. It helps troubleshoot and undo unwanted changes without data loss.

Example Answer: "Oracle Flashback Technology in Oracle 19c enables us to view and recover past database states without the need for traditional point-in-time recovery. This technology is valuable for troubleshooting issues and undoing unintended changes while minimizing data loss."

18. What are Materialized Views, and how are they used in Oracle 19c?

The interviewer is interested in your knowledge of Materialized Views and their applications in Oracle 19c.

How to answer: Explain that Materialized Views are database objects that store the results of a query, providing a way to improve query performance by reducing the need to recompute data frequently.

Example Answer: "Materialized Views in Oracle 19c are database objects that store the results of a query. They are used to enhance query performance by reducing the need to recompute data frequently, which is particularly beneficial for reports and analytics."

19. What is the importance of Oracle Automatic Diagnostic Repository (ADR) in Oracle 19c?

The interviewer is interested in your understanding of ADR and its role in Oracle 19c.

How to answer: Explain that the Oracle ADR is a centralized repository for diagnostic information, making it easier to manage and troubleshoot database issues. It's crucial for efficient problem resolution.

Example Answer: "The Oracle Automatic Diagnostic Repository (ADR) in Oracle 19c is a centralized repository for diagnostic information. It streamlines the process of managing and troubleshooting database issues, ensuring efficient problem resolution and reducing downtime."

20. Explain how the Oracle Partitioning feature works in Oracle 19c.

The interviewer wants to assess your knowledge of Oracle Partitioning and its functionality in Oracle 19c.

How to answer: Describe that Oracle Partitioning allows large tables to be divided into smaller, more manageable partitions, improving query performance and data maintenance. It's particularly useful for tables with large amounts of historical data.

Example Answer: "Oracle Partitioning in Oracle 19c is a feature that enables large tables to be partitioned into smaller segments. This improves query performance and simplifies data maintenance, especially for tables with substantial historical data. It's an excellent solution for data organization and retrieval."

21. What is the Oracle Cloud Database service, and how does it relate to Oracle 19c?

The interviewer is interested in your knowledge of Oracle Cloud Database services and their connection to Oracle 19c.

How to answer: Explain that Oracle Cloud Database services are cloud-based database offerings provided by Oracle, and Oracle 19c is one of the database versions available on these cloud services, allowing businesses to leverage the benefits of cloud computing.

Example Answer: "Oracle Cloud Database services are cloud-based database offerings by Oracle, and Oracle 19c is one of the database versions available on these cloud services. This allows organizations to harness the power of cloud computing while utilizing the robust features of Oracle 19c for their database needs."

22. What is Oracle Real Application Testing (RAT), and how is it used in Oracle 19c?

The interviewer is interested in your knowledge of Oracle Real Application Testing and its role in Oracle 19c.

How to answer: Explain that Oracle Real Application Testing is a feature that allows you to capture and replay real database workloads to assess the impact of changes. It's used for testing changes to ensure they won't negatively affect performance.

Example Answer: "Oracle Real Application Testing (RAT) in Oracle 19c is a powerful tool for capturing and replaying real database workloads. It helps assess the impact of changes, making it a valuable resource for testing and ensuring that changes won't harm database performance."

23. What is Database In-Memory in Oracle 19c, and how does it enhance query performance?

The interviewer wants to assess your understanding of Database In-Memory and its impact on query performance in Oracle 19c.

How to answer: Explain that Database In-Memory is a feature that stores database objects in memory for faster query processing. It enhances performance by reducing I/O and enabling analytical queries to run faster.

Example Answer: "Database In-Memory in Oracle 19c is a feature that stores database objects in memory for quicker query processing. It boosts performance by reducing I/O and enables analytical queries to run significantly faster, making it ideal for data warehousing and reporting."

24. What are some best practices for Oracle 19c database performance tuning?

The interviewer is looking for your knowledge of performance tuning best practices in Oracle 19c.

How to answer: Mention practices like index optimization, SQL tuning, memory management, and using tools like Oracle Enterprise Manager for proactive monitoring and diagnostics.

Example Answer: "Oracle 19c performance tuning involves various best practices. These include optimizing indexes, fine-tuning SQL queries, effectively managing memory resources, and utilizing tools like Oracle Enterprise Manager for proactive monitoring and diagnostics. By implementing these practices, you can ensure optimal database performance."