Oracle MCQ Questions And Answers
Oracle MCQs : This section focuses on "Basics" of Oracle. These Multiple Choice Questions (MCQ) should be practiced to improve the Oracle skills required for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams and other competitive examinations.
1. Oracle database is a ?
A. Centralised database
B. End-user database
C. Commercial database
D. Relational database
View Answer
Ans : D
Explanation: Oracle database is a relational database management system. It is known as Oracle database, OracleDB or simply Oracle.
2. How many editions of the Oracle database there?
A. 2
B. 3
C. 4
D. 5
View Answer
Ans : C
Explanation: There four editions of the Oracle database : Enterprise Edition, Standard Edition, Express Edition and Oracle Lite.
3. A __________ is a single field or combination of fields that contains a unique record.
A. Compound Key
B. Primary key
C. Foreign Key
D. Index
View Answer
Ans : B
Explanation: A primary key is a single field or combination of fields that contains a unique record. It must be filled. None of the field of primary key can contain a null value. A table can have only one primary key.
4. Which statement is used to create a table from an existing table by copying the columns of existing table?
A. CREATE TABLE new_table
AS (SELECT * FROM old_table);
B. CREATE TABLE new_table
(SELECT * FROM old_table);
C. CREATE TABLE new_table
WHERE (SELECT * FROM old_table);
D. CREATE TABLE new_table
LIKE (SELECT * FROM old_table);
View Answer
Ans : A
Explanation: Option A statement is used to create a table from an existing table by copying the columns of existing table
5. A ________ is created by a query joining one or more tables.
A. Trigger
B. Procedure
C. Both A and B
D. View
View Answer
Ans : D
Explanation: A view is created by a query joining one or more tables.
6. Which query is used to add, modify, delete or drop colums of a table?
A. Update
B. Alter
C. Truncate
D. Drop
View Answer
Ans : B
Explanation: Oracle alter query is used to add, modify, delete or drop colums of a table.
7. Which clause is used to remove the duplicate records from the result set?
A. Where
B. Group by
C. Like
D. Distinct
View Answer
Ans : D
Explanation: Oracle DISTINCT clause is used to remove the duplicate records from the result set. It is only used with SELECT statement.
8. How many CREATE TRIGGER statements are there?
A. 4
B. 5
C. 6
D. 7
View Answer
Ans : C
Explanation: There are six CREATE TRIGGER statements according to their firing points : BEFORE INSERT TRIGGER, BEFORE UPDATE TRIGGER, BEFORE DELETE TRIGGER, AFTER INSERT TRIGGER, AFTER UPDATE TRIGGER and AFTER DELETE TRIGGER.
9. view is a virtual table that does not physically exist.
A. TRUE
B. FALSE
C. Can be true or false
D. Can not say
View Answer
Ans : A
Explanation: True, view is a virtual table that does not physically exist.
10. Which is the smallest unit of storage in an Oracle database?
A. Segment
B. Data Block
C. Extent
D. Data File
View Answer
Ans : B
Explanation: Data Block is the smallest unit of storage in an Oracle database
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