1. Question: What is Oracle Database?
- Answer: Oracle
Database is a relational database management system (RDBMS) developed by Oracle
Corporation. It is known for its scalability, reliability, and advanced
features for managing and storing data.
2. Question: Explain the difference between a primary key
and a unique key in Oracle.
- Answer: Both
primary key and unique key constraints ensure the uniqueness of values in a
column or set of columns. The primary key also implies that the column(s)
cannot contain NULL values and is used to identify each row uniquely within a
table.
3. Question: What is PL/SQL, and how does it relate to
Oracle Database?
- Answer: PL/SQL
(Procedural Language/Structured Query Language) is Oracle's procedural
extension to SQL. It allows developers to embed procedural logic within SQL
statements, enabling the creation of stored procedures, functions, and
triggers.
4. Question: How can you optimize a query in Oracle?
- Answer: Query
optimization in Oracle involves creating appropriate indexes, using hints,
gathering statistics, and ensuring that queries are written efficiently.
Analyzing the query execution plan and using tools like Oracle SQL Tuning
Advisor can help identify performance bottlenecks.
5. Question: Explain the purpose of Oracle tablespaces.
- Answer: Oracle
tablespaces are logical storage units that group related database objects
together. They consist of physical data files on disk. Each table and index in
Oracle belongs to a tablespace, allowing for better management of storage.
6. Question: What is the role of the Oracle Data Dictionary?
- Answer: The
Oracle Data Dictionary is a set of read-only tables and views that provide
information about the database. It contains metadata about tables, columns,
indexes, users, privileges, and other database objects.
7. Question: How does Oracle handle transactions, and what
is a rollback segment?
- Answer: Oracle
uses a mechanism known as Automatic Undo Management to handle transactions. A
rollback segment is a storage area used to store old versions of data in case
of a rollback. It ensures data consistency and integrity during transactions.
8. Question: Explain the purpose of the Oracle listener.ora
file.
- Answer: The
listener.ora file in Oracle contains configuration information for the Oracle
Listener, which manages incoming client connections. It specifies details such
as the listening port, protocol, and service handlers.
9. Question: What is the Oracle Data Pump utility, and how
is it different from the traditional exp and imp utilities?
- Answer: Oracle
Data Pump is a modern, high-performance utility for exporting and importing
data and metadata. It is an enhancement over the traditional exp and imp
utilities, providing better performance, parallelism, and additional features.
10. Question: Explain the purpose of the Oracle INDEX hint.
- Answer: The
INDEX hint in Oracle is used to specify the index that the query should use. It
allows developers to influence the optimizer's choice of index during query
execution.
11. Question: What are Oracle sequences, and how are they
used?
- Answer: Oracle
sequences are objects used to generate unique numeric values. They are often
used to generate primary key values for tables and can be used in various
scenarios where unique numbers are required.
12. Question: What is the purpose of the Oracle RMAN
utility?
- Answer: Oracle
Recovery Manager (RMAN) is a utility for managing backup and recovery
operations in Oracle Database. It provides a centralized and efficient way to
perform backup and recovery tasks.
13. Question: How does Oracle handle locks and concurrency
control?
- Answer: Oracle
uses a mechanism called Multi-Version Concurrency Control (MVCC) to handle
locks and ensure concurrency. It allows multiple transactions to read a
consistent snapshot of data, even when other transactions are modifying it.
14. Question: Explain the purpose of the Oracle SQL*Plus
tool.
- Answer: Oracle
SQL*Plus is a command-line tool that allows users to interact with Oracle
Database. It can be used for executing SQL statements, scripts, and managing
database objects.
15. Question: What are Oracle materialized views, and how do
they differ from regular views?
- Answer: Oracle
materialized views are precomputed views stored as tables. They are physically
stored on disk and are useful for improving query performance by storing
aggregated or computed data. Regular views, on the other hand, are virtual and
do not store data themselves.
16. Question: Explain the Oracle Flashback Query feature.
- Answer: Oracle
Flashback Query allows users to view past versions of data in a table by
specifying a timestamp or SCN (System Change Number). It provides a way to
analyze historical data without the need for explicit backups.
17. Question: What is the purpose of the Oracle SQL Tuning
Advisor?
- Answer: The SQL
Tuning Advisor in Oracle is a tool that analyzes SQL statements and provides
recommendations for improving their performance. It suggests changes to
indexes, statistics, and other factors to optimize query execution.
18. Question: How can you secure an Oracle database?
- Answer: Securing
an Oracle database involves implementing strong authentication, configuring
access controls, encrypting sensitive data, applying security patches, and
regularly monitoring and auditing user activities.
19. Question: Explain the concept of Oracle partitioning.
- Answer: Oracle
partitioning is a feature that divides large tables or indexes into smaller,
more manageable pieces called partitions. Each partition can be stored
independently, allowing for improved performance and manageability.
20. Question: What is the purpose of the Oracle
DBMS_SCHEDULER package?
- Answer: The
DBMS_SCHEDULER package in Oracle is used for creating and managing database
jobs, schedules, and programs. It allows users to automate the execution of
tasks, such as running stored procedures or scripts, at specified intervals.
