Explore topic-wise MCQs in Database.

This section includes 42 Mcqs, each offering curated multiple-choice questions to sharpen your Database knowledge and support exam preparation. Choose a topic below to get started.

1.

Which of the following is true about modifying table columns?

A. You can drop a column at any time.
B. You can add a column at any time as long as it is a NULL column.
C. You can increase the number of characters in character columns or the number of digits in numeric columns
D. You cannot increase or decrease the number of decimal places.
Answer» E.
2.

Which of the following is true of SQL views?

A. Oracle views cannot use the ORDER BY clause in view definitions.
B. Oracle views are created using the standard SQL-92 CREATE VIEW command.
C. Oracle views can by queried.
D. The SQL-92 standard does not allow the use of the ORDER BY clause in view definitions.
Answer» B. Oracle views are created using the standard SQL-92 CREATE VIEW command.
3.

Which of the following is true about indexes?

A. Indexes are created to enforce uniqueness on columns.
B. Indexes are created to enable fast retrieval by column values.
C. Columns that are frequently used with equal conditions in WHERE clauses are good candidates for indexes.
D. Indexes are created with the ALTER TABLE command.
Answer» E.
4.

If there is only one statement and no ambiguity about what is wanted, Oracle will treat the semicolon and slash as the same.

A. 1
B.
Answer» B.
5.

Oracle does NOT support a CASCADE UPDATE constraint.

A. 1
B.
Answer» B.
6.

Oracle, the world's most popular DBMS, is powerful and robust, running on many different operating systems.

A. 1
B.
Answer» B.
7.

You can check on the status of tables with the DESCRIBE or DESC command.

A. 1
B.
Answer» B.
8.

The only time that case matters is inside quotation marks of strings.

A. 1
B.
Answer» B.
9.

Oracle directly supports the definition of surrogate keys.

A. 1
B.
Answer» C.
10.

You can use the DROP statement to remove structures from the database.

A. 1
B.
Answer» B.
11.

Sequences guarantee valid surrogate key values.

A. 1
B.
Answer» C.
12.

Oracle will let you define Notepad as your default editor, and whenever you type NOTEPAD, SQL*Plus will invoke Notepad.

A. 1
B.
Answer» C.
13.

When you type Start FILENAME, the statement in your file will be executed automatically.

A. 1
B.
Answer» B.
14.

SQL*Plus is a text editor.

A. 1
B.
Answer» B.
15.

Oracle allows the ORDER BY clause in view definitions.

A. 1
B.
Answer» B.
16.

Money is defined in Oracle with the Currency data type.

A. 1
B.
Answer» C.
17.

When you type into SQL*Plus and press enter, the statement will be finished and executed.

A. 1
B.
C. 1
D.
Answer» C. 1
18.

Which of the following is NOT an Oracle-supported trigger?

A. BEFORE
B. DURING
C. AFTER
D. INSTEAD OF
Answer» C. AFTER
19.

When using SQL*Plus, Oracle commands, column names, table names and all other database elements:

A. are case insensitive.
B. are case sensitive.
C. must always be in lower case.
D. must always be in upper case.
Answer» B. are case sensitive.
20.

Which of the following is not true about modifying table columns?

A. You can drop a column at any time.
B. You can add a column at any time as long as it is a NULL column.
C. You can increase the number of characters in character columns or the number of digits in numeric columns
D. You cannot increase or decrease the number of decimal places.
Answer» E.
21.

The semicolon terminates a SQL statement (and executes it).

A. 1
B.
C. 1
D.
Answer» B.
22.

To see the contents of the SQL*Plus buffer, type:

A. CONTENTS.
B. BUFFER.
C. CURRENT.
D. LIST.
Answer» E.
23.

What is the type of Oracle backup in which all uncommitted changes have been removed from the datafiles?

A. Full backup
B. Consistent backup
C. Inconsistent backup
D. Differential backup
Answer» C. Inconsistent backup
24.

After a table has been created, its structure can be modified using the SQL command:

A. UPDATE TABLE [TableName].
B. MODIFY TABLE [TableName].
C. ALTER TABLE [TableName].
D. CHANGE TABLE [TableName].
Answer» D. CHANGE TABLE [TableName].
25.

SQL*Plus will finish the statement and execute it when the user types in this:

A. A left slash ( \ ) followed by [Enter].
B. A colon ( : ) followed by [Enter].
C. A semicolon ( ; ) followed by [Enter].
D. A period ( . ) followed by [Enter].
Answer» D. A period ( . ) followed by [Enter].
26.

An Oracle System Change Number (SCN):

A. is a value that is incremented whenever a dirty read occurs.
B. is incremented whenever a deadlock occurs.
C. is a value that keeps track of explicit locks.
D. is a value that is incremented whenever database changes are made.
Answer» E.
27.

The default extension for SQL*Plus is .sql.

A. 1
B.
Answer» B.
28.

Which SQL phrase is not supported by Oracle?

A. ON DELETE CASCADE
B. ON UPDATE CASCADE
C. CREATE SEQUENCE [SequenceName]
D. DROP SEQUENCE [SequenceName]
Answer» C. CREATE SEQUENCE [SequenceName]
29.

The default extension for an Oracle SQL*Plus file is:

A. .txt.
B. .pls.
C. .ora.
D. .sql.
Answer» E.
30.

Oracle maintains a System Change Number (SCN) which is a database-wide value that is incremented by Oracle whenever database changes are made.

A. 1
B.
Answer» B.
31.

The left-leaning slash tells Oracle to execute whatever statement is in the buffer.

A. 1
B.
Answer» C.
32.

Oracle commands, column names, table names, view names and all other database elements are case sensitive.

A. 1
B.
C. 1
D.
Answer» C. 1
33.

What Oracle backup and recover file contains user and system data?

A. Control file
B. Datafile
C. OnLine ReDo file
D. Offline ReDo file
Answer» C. OnLine ReDo file
34.

Which of the following is not true of SQL views?

A. Oracle views cannot use the ORDER BY clause in view definitions.
B. Oracle views are created using the standard SQL-92 CREATE VIEW command.
C. Oracle views can by queried.
D. The SQL-92 standard does not allow the use of the ORDER BY clause in view definitions.
Answer» B. Oracle views are created using the standard SQL-92 CREATE VIEW command.
35.

In creating a procedure, you may get a message if you have compile errors. Which of the following is true?

A. The line numbers reported match the line numbers you see in your text editor.
B. SQL*Plus will automatically show the errors to you.
C. To see the errors, enter SHOW ERRORS in SQL*Plus.
D. If there are no syntax errors, you will receive the message "NO ERRORS."
Answer» D. If there are no syntax errors, you will receive the message "NO ERRORS."
36.

Which statement about sequences is not true?

A. A sequence is an object that generates a sequential series of unique numbers.
B. Sequences are most often used to provide values for surrogate keys.
C. NextVal and CurrVal are both sequence methods.
D. Sequences guarantee valid surrogate key values.
Answer» E.
37.

Indexes are created to enforce uniqueness on columns and to enable fast retrieval by column values.

A. 1
B.
C. 1
D.
Answer» B.
38.

What type of failure occurs when Oracle fails due to an operating system or computer hardware failure?

A. Application failure
B. Instance Failure
C. Media Failure
D. Rollback failure
Answer» C. Media Failure
39.

You have linked SQL*Plus to an external text editor. To invoke the text editor for use within SQL*Plus, which command do you use?

A. Open [FileName]
B. Show [FileName]
C. Alter [FileName]
D. Edit [FileName]
Answer» E.
40.

Which prefixes are available to Oracle triggers?

A. :new only
B. :old only
C. Both :new and :old
D. Neither :new nor :old
Answer» D. Neither :new nor :old
41.

Of the three ways to create an Oracle database, which one is the easiest and most recommended?

A. Using the Oracle Database Configuration Assistant.
B. Using the Oracle-supplied database creation procedures.
C. Using the SQL CREATE DATABASE command.
D. None of the above is correct.
Answer» B. Using the Oracle-supplied database creation procedures.
42.

Which of the following is not true about indexes?

A. Indexes are created to enforce uniqueness on columns.
B. Indexes are created to enable fast retrieval by column values.
C. Columns that are frequently used with equal conditions in WHERE clauses are good candidates for indexes.
D. Indexes are created with the ALTER TABLE command.
Answer» E.