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databases Online Quiz - 39

Description: databases Online Quiz - 39
Number of Questions: 20
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Tags: databases
Attempted 0/20 Correct 0 Score 0

Using NVL(),TO_DATE (), TO_NUMBER () functions in 'where' clause on non-indexed columns does improve performance

  1. True

  2. False


Correct Option: A

Which View helps in querying high I/O statements?

  1. V$SQLSTATS.DISK_READS

  2. V$DISK_READS

  3. V$SQL_STATS

  4. V$SYS_STAT


Correct Option: A

Which of the following generates the PLAN for SQL statements?

  1. PLAN

  2. EXPLAIN PLAN

  3. TKPROF

  4. V$PLAN


Correct Option: B

In which version of Oracle is AWR Introduced ?

  1. 11g

  2. 9i

  3. 8i

  4. 10g


Correct Option: D

Is Statspack available in Oracle 11g?

  1. True

  2. False


Correct Option: A

Which of the following is not a schema object?

  1. Indexes

  2. Tables

  3. Public Synonyms

  4. Triggers and Packages


Correct Option: C

AI Explanation

To answer this question, you need to understand the concept of schema objects in a database.

A schema object is a logical database structure that is created and owned by a specific user or schema in a database. These objects are used to store, manage, and manipulate data within the database.

Let's go through each option to understand why it is correct or incorrect:

Option A) Indexes - This option is a schema object. Indexes are database objects that improve the speed of data retrieval operations on database tables.

Option B) Tables - This option is a schema object. Tables are used to store data in a structured manner and are one of the fundamental objects in a database.

Option C) Public Synonyms - This option is not a schema object. Public synonyms are used to provide a consistent and simplified naming convention for database objects across multiple schemas. However, they are not considered as schema objects themselves.

Option D) Triggers and Packages - This option is a schema object. Triggers and packages are database objects used to automate actions and encapsulate related procedures, functions, and variables.

The correct answer is C) Public Synonyms. This option is not a schema object because public synonyms are not considered as schema objects in a database.

If commission is null then the text “Not Applicable” must be displayed, instead of blank space. How do I write the query?

  1. select nvl(to_char(comm),'NA') from emp;

  2. select nvl(comm,'NA') from emp;

  3. select nvl(comm,NA) from emp;

  4. None of the above


Correct Option: A

Which data dictionary object is used to retrieve the information about the tables from a given schema?

  1. USER_TABLES

  2. USER_TABS

  3. Both 1 & 2

  4. None of the above


Correct Option: A

A transaction is a set of SQL statements between any two COMMIT and ROLLBACK statements.

  1. True

  2. False


Correct Option: A

What are the min.extents allocated to a rollback extent ?

  1. One

  2. Two

  3. Three

  4. None of the above


Correct Option: B

What is the maximum no.of columns a table can have ?

  1. 254

  2. 216

  3. Alloted size

  4. None of the above


Correct Option: A

Can Check constraint be used for self referential integrity ?

  1. Yes

  2. No

  3. Not in Oracle

  4. None of the above


Correct Option: A

What are the states of a rollback segment ?

  1. ONLINE

  2. OFFLINE

  3. PARTLY AVAILABLE

  4. NEEDS RECOVERY

  5. INVALID


Correct Option: A,B,C,D,E

What components of the IT environment can Oracle Enterprise Manager Grid Control manage?

  1. The server machines

  2. Oracle application servers

  3. Oracle databases

  4. Third-party products

  5. All of the above


Correct Option: E

Is the below query allowed?Select sal, ename Into x From emp Where ename = 'KING' (Where x is a record of Number(4) and Char(15));

  1. Yes

  2. No

  3. Not in Oracle

  4. None of the above


Correct Option: A

AI Explanation

To answer this question, we need to understand the syntax and rules for the SELECT statement in Oracle.

The SELECT statement is used to query data from a database table. It allows you to specify the columns you want to retrieve, the table you want to query from, and any conditions for filtering the results.

In the given query, the SELECT statement is used to retrieve the "sal" and "ename" columns from the "emp" table. The INTO clause is used to specify that the result of the query should be stored in the variables "x.sal" and "x.ename". The WHERE clause is used to filter the rows based on the condition "ename = 'KING'".

The syntax of the query is correct, and it is allowed in Oracle. Therefore, the correct answer is A) Yes.

A table has the following data : [[5, Null, 10]].What will the average function return ?

  1. 10

  2. 5.5

  3. 5

  4. 7.5


Correct Option: A

Which of these following features are correct if SQL is a set-oriented language?

  1. Individual rows must have a unique identifier

  2. Sets of users can be managed in groups

  3. One statement can affect multiple rows

  4. SQL statements can be placed within blocks of code

  5. All the above


Correct Option: C
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