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programming languages Online Quiz - 70

Description: programming languages Online Quiz - 70
Number of Questions: 20
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Tags: programming languages
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Batch fetching is useful incase of ?

  1. lazy="true"

  2. lazy="false"

  3. lazy="on"

  4. lazy="off"


Correct Option: A

what is the default value in hibernate ?

  1. lazy=false;

  2. lazy=true;

  3. lazy=yes;

  4. lazy=no;


Correct Option: B

HQL is used in ?

  1. session.createQuery();

  2. session.createCriteria();

  3. session.createSQLQuery();

  4. session.lod();


Correct Option: A

What does session.load() return if there is no matching database row ?

  1. NULL

  2. Empty Object

  3. Unrecoverable exception

  4. None of the above


Correct Option: C

AI Explanation

To answer this question, let's understand the purpose of the session.load() method in the context of working with a database.

The session.load() method is used in Object-Relational Mapping (ORM) frameworks, such as Hibernate in Java or SQLAlchemy in Python, to load an object from the database based on its identifier (ID) without actually hitting the database. It returns a proxy object that is associated with the given ID.

In the case where there is no matching database row for the given ID, the session.load() method does not throw any exception or return NULL or an empty object. Instead, it returns a proxy object that represents the requested entity, but the proxy object is not backed by a corresponding row in the database.

Therefore, the correct answer is:

Option C) Unrecoverable exception - This option is correct because the session.load() method does not throw an exception when there is no matching database row. Instead, it returns a proxy object without any data, which might lead to an unrecoverable exception if you try to access properties or perform operations on the proxy object.

Note: It is important to handle this scenario properly in your code to avoid any unexpected behavior or errors.

Does hibernate require persistent classes to implement Serializable?

  1. Required

  2. Not Required

  3. None of the above

  4. None


Correct Option: B

What does CacheMode do ?

  1. controls how a particular SessionFactory interacts with the Data Base.

  2. controls how a particular SessionFactory interacts with the second-level cache.

  3. controls how a particular session interacts with the second-level cache.

  4. None


Correct Option: C

What does sess.delete() do?

  1. a) remove data from in memory

  2. b) remove from database.

  3. c) remove from sessionFactory

  4. d) None of the above.


Correct Option: B
Explanation:

To understand what sess.delete() does, we need to know that it is a method used in SQLAlchemy, which is a Python library for working with SQL databases.

The sess.delete() method is used to delete an object from the database using the SQLAlchemy session object that it is called on.

Now let's go through each option and explain why it is right or wrong:

A. a) remove data from in-memory: This option is incorrect because calling sess.delete() does not remove data from in-memory, it only marks the object for deletion from the database.

B. b) remove from the database: This option is correct. Calling sess.delete() method marks the object for deletion from the database. The object is only removed from the database when the session is committed.

C. c) remove from sessionFactory: This option is incorrect because sess.delete() method does not remove an object from the sessionFactory.

D. d) None of the above: This option is incorrect because option B is correct.

Therefore, the answer is: B. remove from the database.

How can a whole class be mapped as immutable?

  1. By using the mutable="false" attribute in the class mapping.

  2. By using the ismutable="false" attribute in the class mapping.

  3. By using the ismutable="no" attribute in the class mapping

  4. None


Correct Option: A
  1. create tables automatically

  2. create session object automatically

  3. create Session Factory object automatically

  4. None


Correct Option: A
Explanation:

The hibernate.hbm2ddl.auto property is used to automatically create database tables based on the entity classes defined in the Hibernate configuration file.

Option A is correct. When set to create, the hibernate.hbm2ddl.auto property creates the necessary tables in the database based on the entity classes defined in the Hibernate configuration file.

Option B is incorrect. The hibernate.hbm2ddl.auto property doesn't create session objects automatically.

Option C is incorrect. The hibernate.hbm2ddl.auto property doesn't create Session Factory objects automatically.

Option D is incorrect. There is a functionality associated with the hibernate.hbm2ddl.auto property.

Therefore, The Answer is A.

____ forces hibernate to bypass the setter method and access the instance variable directly while initializing a newly loaded object.

  1. By mapping the property with access="onlyfield" in Hibernate metadata

  2. By mapping the property with access="variable" in Hibernate metadata

  3. By mapping the property with access="field" in Hibernate metadata

  4. none of the above


Correct Option: C

Difference between Emp e = session.load(Emp.class) and Emp e = session.createCriteria(Emp.class) ?

  1. On session close session.load() Emp Object unavailable to access.

  2. On session close session.createCriteria() Emp unavailable to access.

  3. None

  4. a & b


Correct Option: A

Which of the following is true?

  1. 1

  2. 66

  3. .1

  4. -1

  5. All of the above


Correct Option: E

What does 7/9*9 equal (in C and C++)?

  1. 1

  2. 0.08642

  3. 0

  4. 7


Correct Option: C

Which of the following is evaluated first:

  1. &&

  2. ||

  3. !

  4. &&&


Correct Option: C

If you continuously increment a variable, it will become negative?

  1. True

  2. False

  3. Cannot continuously increment a variable

  4. It depends on the variable type


Correct Option: D

Which of the following data structures is on average the fastest for retrieving data:

  1. Binary Tree

  2. Hash Table

  3. Stack

  4. Queue


Correct Option: B

Which of the following sorts is quickest when sorting the following set: 1 2 3 5 4

  1. Bubble Sort

  2. Quick Sort

  3. Merge Sort

  4. Radix Sort


Correct Option: A
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