Pandit Deendayal Energy University Assistant Professor Interview Questions and Answers

A page fault is an exception that occurs when a program tries to access a page of memory that is not currently in physical memory.

• Occurs when a program tries to access a page of memory that is not in physical memory

• Causes the operating system to bring the required page into memory from disk

• Can be classified as major or minor depending on whether the page is already in memory but marked as invalid

• Example: When a program...read more

Page replacement techniques are algorithms used in operating systems to manage memory efficiently.

• FIFO (First In, First Out)

• LRU (Least Recently Used)

• LFU (Least Frequently Used)

• Optimal Page Replacement

• Clock Page Replacement

A view in DBMS is a virtual table created by a query that can be used like a regular table.

• Views are used to simplify complex queries by storing them as a virtual table.

• They can also be used to restrict access to certain columns or rows of a table.

• Views do not store data themselves, but instead display data from the underlying tables.

• Changes made to the data in a view will affect the underlying tables.

• Example: CREATE V...read more

Primary key uniquely identifies a record in a table, while foreign key establishes a link between two tables.

• Primary key ensures uniqueness of each record in a table

• Foreign key establishes a relationship between two tables

• Primary key can't have null values, while foreign key can have null values

• Example: In a 'students' table, 'student_id' can be a primary key, while in a 'courses' table, 'student_id' can be a foreign k

The acid properties of a transaction refer to its key characteristics for ensuring reliability and consistency in database systems.

• Atomicity: A transaction is considered atomic if it is treated as a single unit of work that either completes in its entirety or is fully rolled back.

• Consistency: This property ensures that a transaction transforms the database from one consistent state to another consistent state.

• Isolation...read more

DDL commands are used to define the structure of database objects, while DML commands are used to manipulate data within those objects.

• DDL commands include CREATE, ALTER, DROP, TRUNCATE, etc.

• DML commands include INSERT, UPDATE, DELETE, SELECT, etc.

• DDL commands are used to create or modify the structure of database objects like tables, indexes, etc.

• DML commands are used to insert, update, delete, or retrieve data from t

2NF and 3NF are both normal forms in database normalization, with 3NF being a stricter form of normalization than 2NF.

• 2NF eliminates partial dependencies, while 3NF eliminates transitive dependencies.

• In 2NF, every non-prime attribute is fully functionally dependent on the primary key, while in 3NF, every non-prime attribute is non-transitively dependent on the primary key.

• Example: If a table is in 2NF but not in 3NF, i...read more