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databases Online Quiz - 30

Description: databases Online Quiz - 30
Number of Questions: 20
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Tags: databases
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To produce a meaningful result set without any cartesian products, what is the minimum number of conditions that should appear in the WHERE clause of a four-table join?

  1. 8

  2. 2

  3. 3

  4. 4

  5. 5

  6. There is no such criteria


Correct Option: C
  1. TRUNCATE * from TABLE Sales

  2. TRUNCATE TABLE Sales

  3. TRUNCATE Sales TABLE

  4. TRUNCATE * FROM Sales


Correct Option: B

What is true about Sequences?

  1. Once created a sequence belongs to a specific schema.

  2. Once created, a sequence is linked to a specified table.

  3. Once created a sequence is automatically available to all users.

  4. Only the DBA can control which sequence is used by a certain table.

  5. Once created a sequence is automatically used in all INSERT and UPDATE statements.


Correct Option: A,C

What is true about “Parallel Backups” in Oracle 11g? Choose all that apply

  1. If the datafile resides on only one disk, there is no advantage of using parallel backups

  2. The size of all the sections of a datafile involved in “Parallel backup” are always same

  3. The size of all the sections of a datafile involved in “Parallel backup” are always same except the size of the last section

  4. All the sections of one datafile are backed up by the same channel

  5. All the sections of one datafile are backed up by different channels


Correct Option: A,C,E

What is true about “UNDO DATA” in the context of database backups in Oracle 11g using RMAN?

  1. COMMITTED UNDO data is NEVER backed up

  2. COMMITTED UNDO data is backed up depending on the status of the transaction

  3. COMMITTED UNDO data is backed up always

  4. UNCOMMITTED UNDO data is never backed up

  5. UNCOMMITTED UNDO data is backed up depending on the status of the transaction

  6. UNCOMMITTED UNDO data is backed up always


Correct Option: A,F

What is the benefit of “Virtual Private Catalog” feature in Oracle 11g?

  1. Create one catalog database per Database Administrator to share the maintenance workload

  2. Restrict SYSDBA and SYSOPER access from Database Administrators and yet allow them to perform database backup and recovery related tasks i.e. Virtualization of the SYSDBA and SYSOPER access

  3. Maintain only one database for the RMAN repository catalog yet establish secure boundaries for individual database owners to manage their own virtual repositories

  4. Make Oracle 11g database compliant with global Backup and Recovery standards


Correct Option: C

What is true about “IMPORT CATALOG” command? Choose all that apply

  1. It is used to consolidate multiple catalog database repositories into a single catalog database

  2. Once the import is successful, it unregisters the database from the destination catalog database i.e. the database where the metadata is imported

  3. Once the import is successful, it unregisters the database from the source catalog database i.e. the database which holds the original metadata

  4. If NO UNREGISTER clause is used, it will not unregister the database from the destination catalog database i.e. the database where the metadata is imported

  5. If NO UNREGISTER clause is used, it will not unregister the database from the source catalog database i.e. the database which holds the original metadata


Correct Option: A,C,E

What is true about “Database Duplication” in Oracle using RMAN?

  1. Duplicating the database from its backup has been available since Oracle8i Database

  2. Duplicating the database from its backup has been available since Oracle9i Database

  3. Duplicating the database from its backup has been available since Oracle10g Database

  4. Duplicating the database from its backup has been available since Oracle11g Database


Correct Option: B

Which CLAUSE is used in the DUPLICATE DATABASE command to let RMAN know that you aren’t using prior backups of the target database as source but are instead using the network for the database duplication?

  1. from target database

  2. from live database

  3. from source database

  4. from active database


Correct Option: D

PRODUCT ======= Product ID Product Description Manufacturer ID MANUFACTURER ============ Manufacturer ID Manufacturer Name Referring to the above table, what type of relationship exists between the Product table and the Manufacturer table?

  1. Product - Many Manufacturer - Many

  2. Product - One or Many Manufacturer - One or Many

  3. Product - Many Manufacturer - One

  4. Product - One Manufacturer - One

  5. Product - One Manufacturer - Many


Correct Option: B

You have been asked to construct a query in the company's RDBMS. You have deployed a Right Outer Join operation. Referring to the scenario above, what will happen to the final results when there is NO match between the tables?

  1. The right table will return ALL rows

  2. The right table will return NULL

  3. Both tables will return NULL

  4. The left table will return ALL rows

  5. The left table will return NULL.


Correct Option: D

AI Explanation

To answer this question, you need to understand the concept of a right outer join.

A right outer join returns all the rows from the right table (the table mentioned after the "RIGHT OUTER JOIN" keyword in the query) and the matching rows from the left table (the table mentioned before the "RIGHT OUTER JOIN" keyword). If there is no match between the tables, the left table will still return all its rows, but the columns from the right table will have NULL values.

So, in the scenario where there is NO match between the tables, the final result of a right outer join will be:

D. The left table will return ALL rows.

This is because the left table returns all its rows regardless of whether there is a match with the right table.

Which phase of the data modeling process contains security review?

  1. Structure

  2. Design Issue

  3. Data Source

  4. Storage Issue

  5. Operational Process


Correct Option: B

Which statements below are correct for TRUNCATE command

  1. Command is used to delete all the rows of the table.

  2. Command is used to delete complete table structure.

  3. Command free the space used by the table.

  4. Command deletes all the constraints,relations and previleges with other tables


Correct Option: A,C

Which statements are correct for Primary and Unique key constraint?

  1. Primary key constraint creates clustered index by default.

  2. Unique key constraint creates clustered index by default.

  3. Primary key constraint allows null values.

  4. Unique key constraint allows null values


Correct Option: A,D

AI Explanation

To answer this question, let's go through each option to understand why it is correct or incorrect:

Option A) Primary key constraint creates clustered index by default - This option is incorrect. While it is true that a primary key constraint creates an index by default, it does not necessarily create a clustered index. By default, a primary key constraint creates a unique nonclustered index. However, you can choose to create a clustered index on the primary key by specifying it explicitly.

Option B) Unique key constraint creates clustered index by default - This option is incorrect. A unique key constraint, like a primary key constraint, does not create a clustered index by default. It creates a unique nonclustered index. You can choose to create a clustered index on a unique key by specifying it explicitly.

Option C) Primary key constraint allows null values - This option is incorrect. A primary key constraint does not allow null values. It enforces the uniqueness of the key and requires that every value in the column(s) defined as the primary key be unique and not null.

Option D) Unique key constraint allows null values - This option is correct. A unique key constraint allows null values. While it enforces the uniqueness of the key, it allows for one null value in the column(s) defined as the unique key. However, it still enforces that all non-null values must be unique.

Based on the explanations above, the correct answer is A and D.

Which one of the following are NOT characteristics of metadata?

  1. Data about Data

  2. Describes a data dictionary

  3. Self-describing

  4. Includes user data


Correct Option: D

AI Explanation

To answer this question, you need to understand the characteristics of metadata. Let's go through each option to understand why it is correct or incorrect:

Option A) Data about Data - This option is correct. Metadata refers to data about data, providing information about the characteristics and properties of the data.

Option B) Describes a data dictionary - This option is incorrect. While metadata can include information about a data dictionary, it is not the sole purpose of metadata. Metadata describes the data itself, including its structure, format, and relationships.

Option C) Self-describing - This option is correct. One of the characteristics of metadata is that it is self-describing. It contains information that allows users and systems to understand and interpret the data it describes.

Option D) Includes user data - This option is incorrect. User data is not considered metadata. Metadata focuses on providing information about the data, not the actual data itself.

The correct answer is D) Includes user data. This option is incorrect because user data is not considered metadata.

<> and != both are same operator into SQL ?

  1. True

  2. False


Correct Option: A

SELECT * FROM r4r_emp; Above is part of DML in SQL?

  1. True

  2. False


Correct Option: A

AI Explanation

To answer this question, we need to understand the concept of Data Manipulation Language (DML) in SQL.

DML is a subset of SQL that is used to manage and manipulate data within a database. It includes statements such as SELECT, INSERT, UPDATE, and DELETE.

In the given statement, "SELECT * FROM r4r_emp;", it is using the SELECT statement, which is a part of DML. The SELECT statement is used to retrieve data from one or more tables in a database.

Therefore, the correct answer is:

A. True

A tablespace hold objects from different schemes

  1. True

  2. False


Correct Option: A

View contains data.

  1. True

  2. False


Correct Option: B
  1. 10.2.0.1

  2. 10.2.0.3

  3. 10.2.0.2

  4. 10.2.0.4


Correct Option: D
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