4NF Database Normalization: MVD and Fourth Normal Form Quiz and Flashcards

Study Flashcards Play Quiz

Questions and Answers

What concept in database normalization theory specifically deals with relationships between attributes?

Multivalued Dependency (MVD)

In the context of Fourth Normal Form (4NF), what does X need to be in a nontrivial multivalued dependency X ->> Y?

Superkey

Which normal form extension primarily addresses transitive dependencies?

Third Normal Form (3NF)

What does Fourth Normal Form (4NF) aim to eliminate from a relation?

Redundancy caused by non-key attributes with dependencies on other non-key attributes Signup and view all the answers

By achieving both Third Normal Form (3NF) and Fourth Normal Form (4NF), what can be significantly reduced and improved in a database schema?

Redundancy and structure integrity Signup and view all the answers

What is the main function of an operating system?

To provide a connection between the user and the computer hardware Signup and view all the answers

What is a thread in the context of operating systems?

A lightweight process that enables multitasking within a single process Signup and view all the answers

How are new threads or child processes created in an operating system?

By cloning existing processes Signup and view all the answers

What is represented by a Process Control Block (PCB) in relation to processes?

All relevant information about a process Signup and view all the answers

Why is process scheduling necessary in multiprogramming systems?

To maximize CPU utilization by switching between processes Signup and view all the answers

What is the primary advantage of using threads in a program?

To improve performance by enabling concurrent execution Signup and view all the answers

What are the two atomic operations that can be performed on a Semaphore?

Wait and Signal Signup and view all the answers

What is the main difference between a Counting Semaphore and a Mutex?

Mutex allows multiple threads to access a resource simultaneously, while Counting Semaphore restricts access to one thread at a time. Signup and view all the answers

What is one of the necessary conditions for deadlock to occur?

All processes are waiting for resources to be released by another process. Signup and view all the answers

Which algorithm handles multiple instances of the same resource in deadlock situations?

Banker's Algorithm Signup and view all the answers

What type of interrupt is raised when a running program accesses an unmapped memory page?

Page Fault Interrupt Signup and view all the answers

Which page replacement algorithm keeps track of all pages in memory in a queue?

First In First Out (FIFO) Signup and view all the answers

Study Notes

Multivalued Dependency (MVD) and 4NF

Multivalued Dependency (MVD) deals with relationships between attributes within a relation
4NF ensures a relation is free of redundancy arising from multivalued dependencies
A relation is in 4NF if and only if, for every nontrivial multivalued dependency X ->> Y, X is a superkey
4NF aims to eliminate redundancy caused by non-key attributes that have dependencies on other non-key attributes
Achieving both 3NF and 4NF reduces redundancy and improves database schema structure and integrity

Process Scheduling

Objectives of Process Scheduling Algorithm:
Different Scheduling Algorithms exist
Process Scheduling is necessary to reduce waste of CPU time in uniprogramming systems like MS-DOS

Synchronization Tools

A Semaphore is an integer variable accessed only through two atomic operations, wait() and signal()
There are two types of Semaphores: Counting Semaphore and Mutex
Mutex provides mutual exclusion, allowing only one thread to work with the entire buffer at a time

Critical Section Problem

A solution must satisfy three conditions: mutual exclusion, progress, and bounded waiting
Semaphores can be used to solve the critical section problem

Deadlock

A situation where a set of processes are blocked because each process is holding a resource and waiting for another resource
Deadlock occurs if four conditions hold simultaneously: mutual exclusion, hold and wait, no preemption, and circular wait
Methods for handling deadlock include Banker’s Algorithm

Memory Management

Techniques allow memory to be shared among multiple processes
Types of Memory Management: Single Partition Allocation Schemes and Multiple Partition Schemes
Page Fault: an interrupt raised by the hardware when a running program accesses a memory page not loaded in main/virtual memory
Page Replacement Algorithms: First In First Out (FIFO) and others

Operating Systems

The interface between the user and the computer hardware
Types of Operating System (OS):
Threads and Processes:
- A thread is a lightweight process and forms the basic unit of CPU utilization
- A process can perform multiple tasks at once by including multiple threads
- A process is a program under execution, represented by a Process Control Block (PCB)