Oracle technical interview questions and answers are crucial for candidates preparing for database-related roles such as Database Developer, SQL Programmer, DBA, or Data Analyst. Oracle is widely used in enterprise applications, so interviewers frequently test a candidate’s concepts in SQL, PL/SQL, joins, indexing, triggers, views, transaction management, and performance tuning. Companies like TCS, Wipro, Infosys, Capgemini, and Cognizant often include Oracle questions in both technical interviews and written tests. This guide covers the most frequently asked Oracle interview questions with clear explanations, practical examples, and beginner-friendly definitions. Whether you are preparing for a campus placement or an experienced-level interview, mastering these Oracle concepts will help you answer confidently. You can also download Oracle interview PDFs and practice company-wise mock tests to enhance your preparation.
Database professionals can deepen their Oracle expertise by studying PL/SQL programming and understanding DBMS concepts thoroughly
Showing 10 of 113 questions
71. Define Transaction ?
A Transaction is a logical unit of work that comprises one or more SQL statements executed by a single user.
72. What is Read-Only Transaction ?
A Read-Only transaction ensures that the results of each query executed in the transaction are consistant with respect to the same point in time.
73. What is a deadlock ? Explain .
Two processes wating to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically.These locks will be released automatically when a commit/rollback operation performed or any one of this processes being
killed externally.
74. What is a Schema ?
The set of objects owned by user account is called the schema.
75. What is a cluster Key ?
The related columns of the tables are called the cluster key. The cluster key is indexed using a cluster index and its value is stored only once for multiple tables in the cluster.
76. What is clusters ?
Group of tables physically stored together because they share common columns and are often used together is called Cluster.
77. What is an Index ? How it is implemented in Oracle Database ?
An index is a database structure used by the server to have direct access of a row in a table. An index is automatically created when a unique of primary key constraint clause is specified in create table comman (Ver 7.0)
78. What is a Database instance ? Explain
A database instance (Server) is a set of memory structure and background processes that access a set of database files.The process can be shared by all users. The memory structure that are used to store most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.
79. What is the use of ANALYZE command ?
To perform one of these function on an index, table, or cluster:
- To collect statistics about object used by the optimizer and store them in the data dictionary.
- To delete statistics about the object used by object from the data dictionary.
- To validate the structure of the object.
- To identify migrated and chained rows of the table or cluster.
80. What is default tablespace ?
The Tablespace to contain schema objects created without specifying a tablespace name.