Hashing in Data Structure: Function, Techniques [With Examples]

Updated on 24 November, 2021

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Hashing in Data Structure

Hashing in Data Structure

Hashing in Data Structure is a fundamental concept that serves as the backbone for efficient data retrieval and storage mechanisms. Essentially, it involves converting a large or complex key into a smaller, fixed-size value, which is then used as an index to store the actual data in a hash table. This process significantly reduces the time it takes to find an item, as it allows direct access to the data instead of going through each element sequentially. My experience with hashing has been nothing short of transformative, enabling me to handle large datasets with ease and improve the performance of applications dramatically. 

From my early days in the field to my current projects, I’ve seen firsthand how hashing can streamline data processing and storage. The beauty of hashing lies in its simplicity and efficiency, making it a vital tool for anyone working with data structures. In this article, I’ll delve into more in-depth Hashing in Data Structure, exploring its functions and techniques and providing examples. Whether you’re just starting out or looking to deepen your understanding of data structures, I’m excited to share my insights and experiences to help you grasp the power of hashing. 

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This blog will give you a deeper understanding of the hash method, hash tables, and linear probing with examples.

What is Hashing in Data Structure? 

Hashing in the data structure is a technique of mapping a large chunk of data into small tables using a hashing function. It is also known as the message digest function. It is a technique that uniquely identifies a specific item from a collection of similar items.

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It uses hash tables to store the data in an array format. Each value in the array has been assigned a unique index number. Hash tables use a technique to generate these unique index numbers for each value stored in an array format. This technique is called the hash technique.

You only need to find the index of the desired item, rather than finding the data. With indexing, you can quickly scan the entire list and retrieve the item you wish. Indexing also helps in inserting operations when you need to insert data at a specific location. No matter how big or small the table is, you can update and retrieve data within seconds.

The hash table is basically the array of elements and the hash techniques of search are performed on a part of the item i.e. key. Each key has been mapped to a number, the range remains from 0 to table size 1

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Types of hashing in data structure is a two-step process.

  1. The hash function converts the item into a small integer or hash value. This integer is used as an index to store the original data.
  2. It stores the data in a hash table. You can use a hash key to locate data quickly.

Examples of Hashing in Data Structure

The following are real-life examples of hashing in the data structure:

  • In schools, the teacher assigns a unique roll number to each student. Later, the teacher uses that roll number to retrieve information about that student.
  • A library has an infinite number of books. The librarian assigns a unique number to each book. This unique number helps in identifying the position of the books on the bookshelf.

Checkout: Sorting in Data Structure

What is Hash Function in DAA?

The hash function in a data structure maps the arbitrary size of data to fixed-sized data. It returns the following values:  a small integer value (also known as hash value), hash codes, and hash sums. The hashing techniques in the data structure are very interesting, such as: 

hash = hashfunc(key)

index = hash % array_size

The hash function must satisfy the following requirements:

  • A good hash function is easy to compute.
  • A good hash function never gets stuck in clustering and distributes keys evenly across the hash table.
  • A good hash function avoids collision when two elements or items get assigned to the same hash value.

One of the hashing techniques of using a hash function is used for data integrity. If using a hash function one change in a message will create a different hash. 

The three characteristics of the hash function in the data structure are:

  1. Collision free
  2. Property to be hidden
  3. Puzzle friendly

Hash Table

Hashing in data structure uses hash tables to store the key-value pairs. The hash table then uses the hash function to generate an index. Hashing uses this unique index to perform insert, update, and search operations.

It can be defined as a bucket where the data are stored in an array format. These data have their own index value. If the index values are known then the process of accessing the data is quicker.

How does Hashing in Data Structure Works? With Example

In hashing, the hashing function maps strings or numbers to a small integer value. Hash tables retrieve the item from the list using a hashing function. The objective of hashing technique is to distribute the data evenly across an array. Hashing assigns all the elements a unique key. The hash table uses this key to access the data in the list.

Hash table stores the data in a key-value pair. The key acts as an input to the hashing function. Hashing function then generates a unique index number for each value stored. The index number keeps the value that corresponds to that key. The hash function returns a small integer value as an output. The output of the hashing function is called the hash value.

Let us understand hashing in a data structure with an example. Imagine you need to store some items (arranged in a key-value pair) inside a hash table with 30 cells.

The values are: (3,21) (1,72) (40,36) (5,30) (11,44) (15,33) (18,12) (16,80) (38,99)

The hash table will look like the following:

Serial Number Key Hash Array Index
1 3 3%30 = 3 3
2 1 1%30 = 1 1
3 40 40%30 = 10 10
4 5 5%30 = 5 5
5 11 11%30 = 11 11
6 15 15%30 = 15 15
7 18 18%30 = 18 18
8 16 16%30 = 16 16
9 38 38%30 = 8 8

The process of taking any size of data and then converting that into smaller data value which can be named as hash value. This hash alue can be used in an index accessible in hash table. This process define hashing in data structure.

Also Read: Types of Data Structures in Python

Collision Resolution Techniques

Hashing in data structure falls into a collision if two keys are assigned the same index number in the hash table. The collision creates a problem because each index in a hash table is supposed to store only one value. Hashing in data structure uses several collision resolution techniques to manage the performance of a hash table.

It is a process of finding an alternate location. The collision resolution techniques can be named as-

  1. Open Hashing (Separate Chaining)
  2. Closed Hashing (Open Addressing)
  • Linear Probing
  • Quadratic Probing
  • Double Hashing

Linear Probing

Hashing in data structure results in an array index that is already occupied to store a value. In such a case, hashing performs a search operation and probes linearly for the next empty cell.

Linear probing in hash techniques is known to be the easiest way to resolve any collisions in hash tables. A sequential search can be performed to find any collision that occurred.

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Linear Probing Example

Imagine you have been asked to store some items inside a hash table of size 30. The items are already sorted in a key-value pair format. The values given are: (3,21) (1,72) (63,36) (5,30) (11,44) (15,33) (18,12) (16,80) (46,99).

The hash(n) is the index computed using a hash function and T is the table size. If slot index = ( hash(n) % T) is full, then we look for the next slot index by adding 1 ((hash(n) + 1) % T). If (hash(n) + 1) % T is also full, then we try (hash(n) + 2) % T. If (hash(n) + 2) % T is also full, then we try (hash(n) + 3) % T.

The hash table will look like the following:

Serial Number Key Hash Array Index Array Index after Linear Probing
1 3 3%30 = 3 3 3
2 1 1%30 = 1 1 1
3 63 63%30 = 3 3 4
4 5 5%30 = 5 5 5
5 11 11%30 = 11 11 11
6 15 15%30 = 15 15 15
7 18 18%30 = 18 18 18
8 16 16%30 = 16 16 16
9 46 46%30 = 8 16 17

What are the different hashing algorithms

Hashing algorithms are crucial for data security and integrity. Common types include MD5, used for checksums but not secure for cryptography; SHA-1, now deprecated due to vulnerabilities; and SHA-256 and SHA-3 from the Secure Hash Algorithm family, which offer enhanced security for modern needs. Bcrypt is another notable algorithm, designed specifically for secure password hashing by incorporating a salt to prevent attacks.

What are the different types of SHA

The Secure Hash Algorithm (SHA) family consists of several variants, each designed for specific security requirements. The primary types include SHA-1, which is now considered vulnerable and is being phased out; SHA-256 and SHA-512, which are part of the SHA-2 family, offering robust security and commonly used in various security applications and protocols; and SHA-3, the latest member of the family, designed to provide a higher level of security and an alternative to the SHA-2 series. These algorithms differ mainly in their bit length and complexity, providing varying degrees of security and performance.

Double Hashing

The double hashing technique uses two hash functions. The second hash function comes into use when the first function causes a collision. It provides an offset index to store the value.

The formula for the double hashing technique is as follows:

(firstHash(key) + i * secondHash(key)) % sizeOfTable

Where i is the offset value. This offset value keeps incremented until it finds an empty slot.

For example, you have two hash functions: h1 and h2. You must perform the following steps to find an empty slot:

  1. Verify if hash1(key) is empty. If yes, then store the value on this slot.
  2. If hash1(key) is not empty, then find another slot using hash2(key).
  3. Verify if hash1(key) + hash2(key) is empty. If yes, then store the value on this slot.
  4. Keep incrementing the counter and repeat with hash1(key)+2hash2(key), hash1(key)+3hash2(key), and so on, until it finds an empty slot.

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Double Hashing Example

Imagine you need to store some items inside a hash table of size 20. The values given are: (16, 8, 63, 9, 27, 37, 48, 5, 69, 34, 1).

h1(n)=n%20

h2(n)=n%13

n h(n, i) = (h1 (n) + ih2(n)) mod 20

n h(n,i) = (h’(n) + i2) %20
16 I = 0, h(n,0) = 16
8 I = 0, h(n,0) = 8
63 I = 0, h(n,0) = 3
9 I = 0, h(n,0) = 9
27 I = 0, h(n,0) = 7
37 I = 0, h(n,0) = 17
48

I = 0, h(n,0) = 8

I = 0, h(n,1) = 9

I = 0, h(n,2) = 12

5 I = 0, h(n,0) = 5
69

I = 0, h(n,0) = 9

I = 0, h(n,1) = 10

34 I = 0, h(n,0) = 14
1 I = 0, h(n,0) = 1


Conclusion

Hashing in Data Structure is a pivotal concept that underscores the efficiency and effectiveness of data retrieval and storage in computer science. Through the exploration of hash functions, hash tables, and the operational mechanics of hashing, we’ve uncovered how this technique streamlines processes and ensures rapid access to data. Moreover, the discussion on collision resolution techniques, such as linear probing and double hashing, illuminates the adaptability and resilience of hashing in managing data conflicts. 

For mid-career professionals, mastering these aspects of hashing is not merely an academic exercise but a practical necessity. The ability to implement and optimize hashing algorithms can significantly impact the performance of software applications. As we continue to navigate the complexities of data structures, let the principles and examples outlined herein serve as a robust foundation for enhancing your computational problem-solving skills. Remember, the power of Hashing in Data Structure lies in its ability to transform abstract data into a structured, accessible format, paving the way for innovative solutions in the digital age.

You can try out the example to strengthen your data structure knowledge. If you are curious to know more about data structure, check out the upGrad Executive PG Programme in Full Stack Development course. This course is designed for working professionals and offers rigorous training and job placement with top companies.

Frequently Asked Questions (FAQs)

1. What is a hash table?

A hash table is an implementation of an associative array, a structure used in computer programming to implement an abstract data type (ADT). In an abstract data type, the programmer does not need to know about the implementation details of the data type (such as how the data is stored in memory), only the operations that can be performed on the data type. A hash table uses a hash function to compute an index into an array of buckets or slots, from which the desired value can be found. Hash Tables are used to implement map-like data structures. Hash tables are very much in use in modern computers for implementing things like dictionaries (as in python), associative arrays (as in PHP), java hashtables, etc. Hash tables are usually implemented in languages as an array of values sorted by their keys. This makes look up and insert/delete operations very fast, as the data is stored systematically in memory.

2. What are the applications of hashing functions?

Hashing functions are used for several applications in computer science, for example, cryptography and document fingerprinting. The main purpose of a hashing function is to map large amounts of input to a fixed length output. In cryptography, hashing is used to ensure that a message or document has not been tampered with. If the document or message is altered in any way (even a single character), the hash value is also altered. It is therefore almost impossible to create a document or message with a given hash value.

3. What are the collision resolution techniques in hashing?

Collision resolution techniques in hashing are used to resolve collisions in hashing. Collision resolution techniques are either chaining or open addressing. In chaining, we retain the old element in place and insert the new element in the next available space. It is a simple method of collision resolution but has a drawback of poor performance. In open addressing, we replace the old element with new element and mark the old element as a collision.

4. What is key in hashing?

These are types of hashing in a data structure, the static hashing gives access to the user to lookup at the finalised dictionary, the finalised dictionary cannot be changed. Whereas, the dynamic dictionary allows the data to be moved based on the demand, as the data can be added or removed. The final result also changes the basis of the records.

5. What is meant by public key?

It is a key available to other people. Its common uses are the transfer of bitcoins, securing web sessions, etc. There is no compromise on the security as two keys are required.

6. What is private key used for?

It is a way to encrypt or decrypt data. For example, If I send a locked file to my friend over mail that is password protected. My friend is aware of the passcode, so they would decrypt the file by inserting the passcode. Private key is efficiency as only single key is required.

7. What is SSH public key?

SSH is a combination of a public or private key. SSH is a pair of keys used to authenticate and decrypt a message from a remote location. The public key can be accessed by both the stakeholders and the remoter servers.

9. What is a hash table in data structures?

A hash table is a data structure that stores data in an associative manner, using a hash function to compute an index into an array of slots or buckets from which the desired value can be found. This allows for efficient searching, as the direct access nature of the hash table reduces the need for iterative searches.

10. What is a collision in hashing in data structures?

A collision in hashing occurs when two different keys hash to the same index in a hash table. To resolve collisions, methods such as chaining (where each bucket stores multiple items as a linked list) or open addressing (where a sequential or probing search is conducted to find an empty slot) are used.

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Rohan Vats

Software Engineering Manager @ upGrad. Passionate about building large scale web apps with delightful experiences. In pursuit of transforming engineers into leaders.

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Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript Check out upGrad’s Advanced Certification in DevOps  To learn Python, I’d strongly recommend Zed Shaw’s Learn Python the Hard Way and Albert Sweigart’s Automate the Boring Stuff with Python. If you’ve decided to go with PHP, you can learn the basics of the language on Codecademy. You already know enough JavaScript syntax to get your hands dirty with the Node and backend JS frameworks (such as Express). I’ll cover Ruby later in conjunction with Rails as it is rarely used as a standalone language. Step 9: Learn SQL For the next step, you should probably pick up a little SQL (Structured Query Language). It is the language databases communicate with. And although you might not use it directly when you switch to using frameworks, it still helps to know how to directly communicate with your database. The good news is that SQL is incredibly easy to learn. You should be able to get a good grasp of it in a matter of hours. Head First SQL is a great resource for this purpose. How to Become a Full Stack Developer: Part 1 upGrad’s Exclusive Software Development Webinar for you – SAAS Business – What is So Different? document.createElement('video'); https://cdn.upgrad.com/blog/mausmi-ambastha.mp4   Step 10: Learn a ‘Conventional’ Full-Stack Web Framework Now is a good time to experiment with web frameworks that can do most of the lower level work for you. There isn’t a shortage of great frameworks that could cater to every purpose imaginable. Rails (written in Ruby), Spring (written in Java) and Django (written in Python) are among the popularly used frameworks today. You could take a look at Michael Hartl’s The Rails Tutorial – available for free. As far as Django is concerned, the tutorial on the official website is a good place to start. Once you feel you’re comfortable with the basics of the framework, do give Two Scoops of Django a read. It’s one of the best technology books ever. If you’ve decided to go the Spring route, I’d strongly suggest signing up for UpGrad & IIIT-B’s Software Development program. The program gives you a very holistic overview of the framework and helps you build a robust and scalable backend. Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses Step 11: Javascript Full-Stack Frameworks and the MEAN Stack Not very long ago, Backend Development used to be based on the concept of the request-response cycle. For example, the browser sent a request and the server responded by spitting out a webpage in HTML. However, since early 2010, more and more applications have become real time. The structure of an entire web page changes without refreshing and behaves dynamically based on user input and interaction (Think chat, liking, commenting, live videos and reactions, etc.). In such a scenario, a simple request-response cycle simply isn’t enough. Therefore, there has been a recent surge of interest towards asynchronous programming and making AJAX requests the norm. Javascript Frameworks tend to excel at this. So, it makes sense to get acquainted with one of the major JS frameworks available in the market. The two most popular ones are the MEAN Stack and MeteorJS. Interview with Farooq Adam, Co-Founder, Fynd Learning MEAN is slightly more complicated due to its asynchronous nature and the callback hell Node usually tends to unleash. But now that you’re a seasoned developer, you are mature enough to deal with its idiosyncrasies. Meteor is a full-stack JS framework I’m currently experimenting with. The concept of Meteor is absolutely delightful – one framework in one language that takes care of all the components of an application (front-end, back-end, and database). However, this comes at the cost of customisation freedom. Once you’ve built something in Meteor, it is virtually impossible to change the database or the backend framework should you choose to do so. Though, I still think this is a worthwhile technology to learn. Meteor is known to be extremely powerful. It’s capable of doing things in hundreds of lines of code where other conventional frameworks would’ve required a thousand. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses Conclusion This is the end of part 2. In this post, we’ve covered resources concerning backend development and the various full-stack technologies available. You can now proudly call yourself a full-stack developer. Congratulations! But the story of full-stack web development doesn’t end here. With the introduction of the iPhone, there has been a smartphone revolution around the globe. More and more people are shifting towards using smartphones in place of desktops. In such a scenario, it is imperative that you learn to build apps for two of the most popular platforms out there: Android and iOS. We shall be covering this in the next and final part of this series. Additionally, we shall also look into frameworks that allow us to build native apps using Javascript (Ionic, React Native, etc.). Until then, it’s goodbye. 🙂 Your comments and suggestions are welcome! Read our Popular Articles related to Software Development Why Learn to Code? How Learn to Code? How to Install Specific Version of NPM Package? Types of Inheritance in C++ What Should You Know?
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by Rounak Banik

01 Dec'17
How to Become a Full-Stack Developer: Part 3

5.29K+

How to Become a Full-Stack Developer: Part 3

This post is the third and final in the series on becoming a full-stack developer. This article talks specifically about mobile app development. Read here for more on frontend and backend development. When Steve Jobs introduced the iPhone in 2007, it ushered the biggest revolution the world had witnessed since the printing press. Smartphones have managed to penetrate almost every country on the globe. Even the most impoverished seem to be in possession of one so much so that life without them seems inconceivable. Check out our free courses to get an edge over the competition Motivation There are certain apps which make sense only when running on a phone. Take Uber, for instance. Uber needs to know your exact location through GPS. An Uber app for desktop wouldn’t make much sense. Another issue is that a majority of your audience will open your app through a phone, even if it is one that has been built for browsers. In such cases, it is imperative that you ensure the experience is seamless and too much data isn’t consumed. Finally, there are subtle differences between interacting using mouse-clicks and touch. Your app must ensure that it behaves well in both scenarios. Keeping all these considerations in mind, it makes good sense to venture out of the browser and build mobile apps. This ensures that you make maximum use of the functionalities a typical smartphone has to offer while at the same time making the user experience a delight. Below are the steps to acing mobile app development. For the first part to become a full stack developer on frontend and backend development. Check out upGrad’s Advanced Certification in Blockchain Learn Software Development Courses online from the World’s top Universities. Earn Executive PG Programs, Advanced Certificate Programs or Masters Programs to fast-track your career. Interview with Ankit Tomar, Co-Founder & CTO, Bizongo Step 12: Choose a Platform The first step would be to choose a platform where you would like to build your application. Unless you’re part of a reasonably big team, it is extremely unlikely that you will build apps from scratch on all major platforms. The more likely scenario is that you will be coding on your favourite platform and will then simply port it over to the others. The major smartphone platforms today are iOS, Android, and Windows. They use drastically different languages and IDEs. For instance, iOS uses Swift and XCode, Android uses Java and the Android Studio and Microsoft operate with C# and Visual Studio. upGrad’s Exclusive Software Development Webinar for you – SAAS Business – What is So Different? document.createElement('video'); https://cdn.upgrad.com/blog/mausmi-ambastha.mp4   Check out upGrad’s Advanced Certification in DevOps  The market today is dominated by Android and iOS, so the choice really comes down to these two. Some things you may need to consider before making a choice is the audience share for your app. I believe it makes good business sense to build iOS apps if you’re in a First World country as Apple Devices are extremely popular there. In contrast, in a country like India, Android would be a more obvious choice as the market share for iPhones is extremely small owing to its exorbitant price. If you plan on making money from your app, keep in mind that iOS users are more likely to open their wallets for in-app purchases than their Android counterparts. This may be because iOS users usually tend to have more disposable income as compared to third world markets where Android dominates. iOS development requires you to have a Mac Development machine. Also, Apple App Store licenses retail at $99/year compared to Google Play’s one time $25 fee. In other words, iOS development is considerably more expensive. In this post, I shall cover how mobile app development is done today: Native Android Apps, Native iOS Apps and Hybrid Mobile Apps. Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript Step 13: Java and XML Java is the most popular language for Android Development (Google has recently introduced support for the Kotlin Programming language too). The founders of Android thought Java to be an appropriate choice and they have stuck to it since its inception. And if their trajectory is anything to go by, it has been nothing short of an amazing decision. The best resource to learn Java would be Head First Java. Reading this book will give you a thorough introduction to the language as well as Object Oriented Programming Principles. As far as XML is concerned, I do not think you need a concentrated tutorial on the subject. You’ve already worked extensively with a subset of XML (HTML) and you will be able to figure it out pretty quickly, even if you were to jump directly into Android development. I cannot say the same for Java. Ensure you have a good grasp of the language before venturing into Android. Step 14: Android You now have the technical know-how to build Android apps. It is time to dive deep into this revolutionary OS. Be wary though that certain Android practices differ from what you usually see on the web. The resources I’ve suggested below will ensure that your learning is not hindered by these differences. Android Programming- The Big Nerd Ranch Guide 2nd Edition is a good place to start if you know Java already. Make sure you pick up the second edition as that is the one that uses Android Studio, which is the industry standard now. The practice of building apps in Eclipse is largely outdated. Interview with Farooq Adam, Co-Founder, Fynd Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses Step 15: iOS If you are more of an Apple aficionado and/or have decided that iOS apps make more sense to your business/career aspirations. The first step would be to acquire a Mac. XCode works only on Mac and in order to publish on the app store, you need a Mac. Sorry, VMWare. The resource I’m going to suggest for iOS is exactly the same as that for Android. Nerd Ranch has its own publication – iOS Programming: The Big Nerd Ranch Guide which deals with Swift and XCode, so that is a good place to start. Step 16: Hybrid Mobile Apps If you’re a solo developer or are working in a small team, you probably do not have the time or the resources to separately build and maintain Android and iOS Apps. To alleviate the developer’s pain of building for multiple platforms, the concept of Hybrid Mobile Apps was introduced. The concept is extremely simple and revolutionary. If you know Javascript, you already know how to build web apps. Therefore, should you have an app in JS, there must exist a framework that automatically ports your application into Android, iOS, and Windows. Incredible but true. Most hybrid frameworks achieve this using Cordova or React Native. You can think of Cordova as the bridge between browsers and the smartphone’s native hardware. It establishes a connection between the two solely using JS and helps in creating the build scripts in the native languages of each platform. Cordova based frameworks, however, are rapidly being overshadowed by Facebook’s powerhouse, React Native. The power of React Native lies in the fact that while Cordova constructs WebViews, React Native lets you build native apps that you’d build using either Java (for Android) or Swift (for iOS). In other words, Cordova is a website disguised as a mobile app, but React Native lets you build the real thing. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses In my opinion, you can give Cordova a miss and learn React Native instead. It is an extremely great career investment to make. UpGrad & IIIT-B’s Software Development program is a great place to start your journey with this revolutionary library which has already been used by companies like Facebook, Netflix and AirBnB to design their apps. Interview with Farooq Adam, Co-Founder, Fynd Conclusion With the conclusion of hybrid apps, we come to an end of this series. In summary, these are the things we’ve covered: Computer Science Fundamentals. Data Structures and Algorithms UI/UX HTML, CSS, JS Front-End Frameworks Server-Side Scripting and Databases Full Stack Frameworks Android and iOS Hybrid Mobile Apps Read our Popular Articles related to Software Development Why Learn to Code? How Learn to Code? How to Install Specific Version of NPM Package? Types of Inheritance in C++ What Should You Know? I hope you’ve enjoyed reading this series as much as I have enjoyed writing it and more importantly, found at least some parts useful. As always, your comments and suggestions are welcome!
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by Rounak Banik

01 Dec'17
Why Companies are Looking to Hire Full Stack Developers

7.08K+

Why Companies are Looking to Hire Full Stack Developers

It’s no secret that companies today are looking to hire young and talented software developers. But with so many smart developers out there, how can you set yourself apart from everyone else applying for these coveted roles? The best way to do this is to master the skills companies demand: a wide variety of programming skills. When you are learning how to develop software, you can improve your odds of getting a job by learning full stack development. In fact, Indeed ranked the Full Stack Developer role as the #1 job in 2017. Check out our free courses to get an edge over the competition. There are three main reasons why companies love to hire young full stack developers: Full stack developers can solve many problems Companies look to hire people based on what problems the candidates can solve for the company. By definition, full stack developers can work on both backend, frontend, and the protocols that connect the two; being able to create a software product end to end and independently. When you learn full stack development, you have an advantage over other job seekers as you can solve many more problems than other developers. For example, think about working at a high growth startup. Startups need developers who can work on a variety of programming projects. From user interfaces to server-side programming, to database applications, and everything in between. With only a small team, startups want to hire full stack developers who can work on many of the different software projects. As a full stack developer, you build many types of software projects that most other developers cannot. Check out upGrad’s Full Stack Development Bootcamp (JS/MERN) Even at a larger company, hiring developers with the knowledge to work on many different projects gives a manager flexibility to move people between teams as businesses constantly need change. One year, you can have a developer work on a frontend project and then you can move him to a backend project the very next year. The added flexibility makes the manager’s job much easier so they like to work with developers with a wide variety of skills. Check out upGrad’s Java Bootcamp.   How to Become a Full Stack Developer Companies love full stack developers because they can solve many different problems for the business. Companies like to hire young developers who are generalists The main reason is that companies hire young developers based on their potential rather than deep domain knowledge. Companies like to teach young developers what they want them to know. As a full stack developer, you have a broad set of technology skills that the company can help you expand further. As an entry-level developer, they don’t need you to understand every algorithm. But you need to have core programming knowledge so the company can teach you what is specific to their business. Let’s go back to the example of working at a startup. When the company is starting out, they need full stack developers to work on all layers of the development stack, but as the company grows, the developers will need to specialise. It’s easy for a full stack developer to start as a generalist and then become a specialist later as the company can hire more employees. On the other hand, it’s very difficult for a specialist to join a startup and learn to be a generalist when the company is small. Full stack developers can grow with their companies more easily than specialists can. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses Once you know the basics and get the job, the company will invest time and money to help you expand your knowledge further. Full stack developers can become great managers and executives Companies love to promote people with a wide variety of experiences in the business. As a full stack developer, you will get a chance to work on frontend software, backend software, and all of the architecture that connects them. Through that variety of experience on different projects, you get the opportunity to learn much more than your solely backend and frontend peers. They only get a chance to learn one part of the company’s technology architecture, but you learn the whole architecture and understand how it all fits together. That puts you in a great opportunity to rise through the technology ranks of the company and get promoted. If you work at a startup, your experience as a full stack developer can help set you apart from your peers as the company grows. Where some developers only know how one part of the technology stack works, you understand how all aspects of the technology fit together. As more developers are hired and new technology teams form, you are more likely to manage those new teams because of your wide knowledge. At a large company, you may also get more chances for promotion. When companies look to promote from within, they need people who can manage cross-functional software teams. As a full stack developer, you will know how to talk to developers from both frontend and backend teams. How to Succeed in Your First Software Development Job Of course, technology skills are not the only ones needed to get you a promotion. You will also need to learn business skills to be a manager. But if you do that you can climb high up the corporate ladder. Looking to become a full stack developer? This article does a great job explaining how to get started: How to become a full stack developer. Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript Enroll in Software Engineering Courses from the World’s top Universities. Earn Executive PG Programs, Advanced Certificate Programs, or Masters Programs to fast-track your career.
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by Gopi Vajravelu

31 Jan'18
What is Test-driven Development: A Newbie’s Guide

5.49K+

What is Test-driven Development: A Newbie’s Guide

Programmers and bugs have been in a never-ending fight for supremacy since time unknown. It’s unavoidable – even the best programmers fall prey to bugs. No code is truly safe from bugs, that’s why we perform testing. Programmers, at least the sane ones, test their code by running it on development machines to make sure it does what it was meant to do. Traditionally, test cases were written after writing the code, but in Test-driven Development, an automated test case is written before writing any piece of code so that the execution and testing can be checked simultaneously. In this article, we’ll be talking about Test-Driven Development in depth and why is it better than the traditional methods! Check out our free courses to get an edge over the competition   What is Test-Driven Development? Test-Driven Development was created as part of the Extreme Programming (XP) methodology and was called the ‘Test-First’ concept. Test-driven development allows you to test your code thoroughly, and also enables you to retest your code quickly and easily since it’s automated. In essence, before writing any piece of code, the programmer first creates a unit-test. Then, the programmer creates just enough code to satisfy the unit-test. Once the test is passed and the code refactored, the programmer can go ahead with making further improvements. Test-driven development makes sure that the code is thoroughly tested which leads to a modularized, extensible, and flexible code. Each time a new feature is to be added, it needs to undergo what is called the “lifecycle” of TDD. Let’s talk more about this lifecycle. Check out upGrad’s Advanced Certification in DevOps How to Become a Full Stack Developer Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript Test-Driven Development Lifecycle The test-driven development lifecycle covers everything from writing the initial unit-test to reworking the code. Add a test: Every new feature needs to undergo a test before its implemented. The essential requirement for writing a test is to have a clear understanding of all the requirements. This is accomplished using use-cases and user-stories.   Run all tests and check the net test: This is done to ensure the correct working of our test. Basically, this phase aims to check that the test is not passed by any code that doesn’t meet the requirements. By doing so, this step eliminates the possibility of having a faulty test at hand.   Write code: Now that you have your test in place, the next obvious step is to write a code that clears the test. This code need not be perfect in all aspects, but it needs to clear the test. Once we’re sure this code clears the test, it can be modified as per the requirements.   Run the tests: Having written the code, now it’s time to see if the code passes the test or not. If your code passes the tests, it means that your code meets the requirements – till now.   Refactor the code: This is essentially done to clean up the code. Refactoring doesn’t cause damage to any of the functionalities; it is just for cleaning the code by removing duplication between test code and production code.   Repeat: This cycle is now repeated with a fresh test to add more functionalities. Each functionality undergoes the same cycle. Essentially, the size of steps should be not more than 1-10 edits between each test run. If a code doesn’t pass the test rapidly, the developer must revert and not debug excessively. Check out upGrad’s Full Stack Development Bootcamp (JS/MERN)  Why Companies are Looking to Hire Full Stack Developers Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses The Pros and Cons of Test-Driven Development Test-driven development has some definite pros over traditional methods of testing – which were mostly manual. However, it’s not infallible. Just like any other technology, the test-driven development also has a set of cons. Let’s have a look at what are the benefits of TDD in detail: Writing small tests ensures modularity of your code. Practicing TDD helps you understand the underlying principles of good modular design.   TDD provides clarity during the implementation of your code which enables a safety-net during the refactoring phase.   With TDD, collaborating is a lot easier as now people can edit the code with confidence because the test will inform them if their changes are not up to the mark of the test.   The base of TDD is unit-tests. Because of that, refactoring is a whole lot easier and faster. Refactoring an old code is a pain, but if the code is backed by unit tests, it becomes so much easier.   It helps in clarifying all the requirements before you begin the coding part. This way, a lot of ambiguity that can arise later on is avoided.   Test-driven development focuses on testing while writing. This forces the programmer to make their interfaces clean enough to pass the test. It’s hard to understand this advantage until you work on a piece of code that hasn’t undergone TDD.   Silly mistakes are caught almost immediately. It helps in removal of those mistakes that would waste a lot of time if found in QA. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses Now, let’s have a look at what are the limitations of test-driven development: The test suite that’s used for testing needs to be maintained else the tests may not be fully deterministic.   The tests are hard to write – especially beyond the unit-testing phase.   TDD does slow down the pace of development, at least initially.   Like with any form of development, there’s a big difference between just doing it and doing it well. Writing good unit tests requires a level of specialty.   It’s difficult to apply this approach to your legacy(existing) code.   TDD requires you to perform routine housekeeping. It’s necessary to refine the tests to make them run more quickly.   It’s easy to get distracted by the fancy features in any unit-testing framework, but it should be kept in mind that simple tests tend to give the best results.   Unless everyone on the team correctly maintains their tests, the whole system can quickly degrade. How to Succeed in Your First Software Development Job Read our Popular Articles related to Software Development Why Learn to Code? How Learn to Code? How to Install Specific Version of NPM Package? Types of Inheritance in C++ What Should You Know? In Conclusion… Test-driven development is the way forward as far as future of application development goes. There are a number of automated testing frameworks like PHPUnit, Serenity, Robot, RedWoodHQ, and many more. Pick the one that fits your need and get started with building better maintainable applications in no time!  Enroll in Software Engineering Courses from the World’s top Universities. Earn Executive PG Programs, Advanced Certificate Programs, or Masters Programs to fast-track your career.
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by Arjun Mathur

12 Mar'18
A Beginner’s Guide to MVC Architecture in Java

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A Beginner’s Guide to MVC Architecture in Java

If you’re related to web development scene, you’ll most certainly have come across the acronym “MVC” hundreds of time, if not more. MVC is one of the most talked about design patterns in the web programming world today, and rightly so. In this article, we’ll take you through the world of MVC Architecture. We’ll talk about the basics of MVC, its advantages, and finally, a simple code that will help you understand the implementation of MVC in Java in a clearer way. What exactly is the MVC architecture? Before we get into the technicalities of it, let’s make some things clear – MVC is NOT a design pattern, it’s a way to structure your applications. In recent years, the web applications are extensively using the MVC architecture, and hence it’s natural to confuse it for a design pattern exclusive for web applications. However, let’s tell you that MVC was first described way back in 1979 – before the WWW era when there was no concept of web applications. The architecture used today for web applications is an adaptation of the original pattern. In fact, this architecture was initially included in the two major web development frameworks – Struts and Ruby on Rails. These two environments paved the way for a majority of web frameworks that came later – and thus the popularity of this architecture kept rising. Learn to build applications like Swiggy, Quora, IMDB and more MVC architectural pattern follows an elementary idea – we must separate the responsibilities in any application on the following basis: Model: Handles data and business logic. View: Presents the data to the user whenever asked for. Controller: Entertains user requests and fetch necessary resources. Each of the components has a demarcated set of tasks which ensures smooth functioning of the entire application along with complete modularity. Let us have a look at each of these components in further detail. Check out our free courses to get an edge over the competition. Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript upGrad’s Exclusive Software and Tech Webinar for you – SAAS Business – What is So Different? document.createElement('video'); https://cdn.upgrad.com/blog/mausmi-ambastha.mp4   Controller The controller is the like the housekeeper of the application – it performs coordination between model and view to entertain a user request. The user requests are received as HTTP get or post request – for example, when the user clicks on any GUI elements to perform any action. The primary function of a controller is to call and coordinate with the model to fetch any necessary resources required to act. Usually, on receiving a user request, the controller calls the appropriate model for the task at hand. Check out upGrad’s Full Stack Development Bootcamp (JS/MERN) Model The model is quite simply the data for our application. The data is “modelled” in a way it’s easy to store, retrieve, and edit. The model is how we apply rules to our data, which eventually represents the concepts our application manages. For any software application, everything is modelled as data that can be handled easily. What is a user, a book, or a message for an app? Nothing really, only data that must be processed according to specific rules. Like, the date must not be higher than the current date, the email must be in the correct format, the name mustn’t be more than “x” characters long, etc. Check out upGrad’s Java Bootcamp Whenever a user makes any request from the controller, it contacts the appropriate model which returns a data representation of whatever the user requested. This model will be the same for a particular work, irrespective of how we wish to display it to the user. That is why we can choose any available view to render the model data. Additionally, a model also contains the logic to update the relevant controller whenever there is any change in the model’s data. Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses View As the name suggests, the view is responsible for rendering the data received from the model. There may be pre-designed templates where you can fit the data, and there may even be several different views per model depending on the requirements. Any web application is structured keeping these three core components in mind. There may be a primary controller that is responsible for receiving all the requests and calling the specific controller for specific actions. Let’s understand the working of a web application under the MVC architecture better using an example. Let’s See an Example Let’s take an example of an online stationery shop. The user can view items, buy, add items to cart, add items to current order, or even add/remove items (if he’s the admin). Now, let’s see what will happen when a user clicks on the title “Pens” to see the list of pens. Our application will have a particular controller to handle all the queries related to pens. Let’s say it’s called “pens_controller.php”. We’ll also have a model that will store the data regarding the pens we have – let’s call it “pens_model.php”. Finally, we’ll have several views to present the data – a list of pens, a table displaying pens, a page to edit the list, etc. The following figure shows the complete flow of control right from the moment a user clicks on “pens”, to when the result is rendered in front of him: First, the “pens_controller.php” handles the user request (1) as a GET or POST request. We can also have an “index.php” which is the central controller which will call the “pens_controller” whenever needed. The controller then examines the request and the parameters and calls the required model – in this case, “pens_model.php”. The controller asks the model to return the list of available pens (2). Now, the model searches the database for the necessary information (3), applies logics if necessary, and returns the data to the controller(4). The controller then picks an appropriate view (5) and presents the data (6 and 7). If a request comes from a handheld device, a view suitable for it will be used, or if the user has a particular theme selected, its view will be picked – and so on. How to Become a Full Stack Developer The Advantages of the MVC Architecture A common problem faced by application developers these days is the support for different type of devices. The MVC architecture solves this problem as developers can create different interfaces for different devices, and based on from which device the request is made, the controller will select an appropriate view. The model sends the same data irrespective of the device being used, which ensures a complete consistency across all devices. The MVC separation beautifully isolates the view from the business logic. It also reduces complexities in designing large application by keeping the code and workflow structured. This makes the overall code much easier to maintain, test, debug, and reuse. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses A Simple Implementation of MVC using Java We will have the following three: StudentObject : the model.   StudentView: view class to print details on the console.   StudentController: a controller that stores data in studentObject and updates StudentView accordingly Step 1: Create the Model public class Student {   private String rollNo;   private String name;      public String getRollNo() {      return rollNo;   }      public void setRollNo(String rollNo) {      this.rollNo = rollNo;   }      public String getName() {      return name;   }      public void setName(String name) {      this.name = name;   } } The code is self-explanatory. It consists of functions to get/set roll number and names of the students. Let’s call it “student.java”. Step 2: Create the View public class StudentView {   public void printStudentDetails(String studentName, String studentRollNo){      System.out.println("Student: ");      System.out.println("Name: " + studentName);      System.out.println("Roll No: " + studentRollNo);   } } This is simply to print the values to the console. Let’s call this “studentView.java”. Step 3: Create the Controller public class StudentController {   private Student model;   private StudentView view;   public StudentController(Student model, StudentView view){      this.model = model;      this.view = view;   }   public void setStudentName(String name){      model.setName(name);   }   public String getStudentName(){      return model.getName();   }   public void setStudentRollNo(String rollNo){      model.setRollNo(rollNo);   }   public String getStudentRollNo(){      return model.getRollNo();   }   public void updateView(){      view.printStudentDetails(model.getName(), model.getRollNo());   } } Call this “StudentController.java”. A cursory glance will tell you that this controller is just responsible for calling the model to get/set the data, and then updating the view. Now, let’s have a look at how all of this is tied together. Step 4: Create the main Java file public class MVCPatternDemo {   public static void main(String[] args) {      //fetch student record based on his roll no from the database      Student model  = retriveStudentFromDatabase();      //Create a view : to write student details on console      StudentView view = new StudentView();      StudentController controller = new StudentController(model, view);      controller.updateView();      //update model data      controller.setStudentName("John");      controller.updateView();   }   private static Student retriveStudentFromDatabase(){      Student student = new Student();      student.setName("Robert");      student.setRollNo("10");      return student;   } } This is called “MVCPatternDemo.java”. As you can see, it fetches the student data from the database or a function (in this case we’re using a function to set the values) and pushes it on to the Student model. Then, it initialises the view we had created earlier. Further, it also initialises our controller and binds it to the model and the view. The updateView() method is a part of the controller which updates the student details on the console. Step 5: Test the Result If everything goes right, the result should be: Student: Name: Robert Roll No: 10 Student: Name: John Roll No: 10 If you get this as the output, congratulations! You’ve successfully implemented the MVC architecture using Java, albeit for a simple application. However simple, this application is enough to demonstrate the powers of the MVC architecture. 15 Must-Know Spring MVC Interview Questions Wrapping Up… After so much said and done, it’s hard to emphasise more on the power of the MVC architecture in any web/desktop application these days. It provides an altogether new level of modularity to your code which makes it a lot more readable and maintainable. So, if you want to scale to new heights in your career as an application developer, getting hold of the MVC architecture and its working should be your top priority. Read our Popular Articles related to Software Development Why Learn to Code? How Learn to Code? How to Install Specific Version of NPM Package? Types of Inheritance in C++ What Should You Know? Enroll in Software Engineering Courses from the World’s top Universities. Earn Executive PG Programs, Advanced Certificate Programs, or Masters Programs to fast-track your career. Do drop by a comment and let us know how you like this article!
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by Arjun Mathur

09 Apr'18
What is the Future Scope of Full Stack Developer in India?

11.3K+

What is the Future Scope of Full Stack Developer in India?

Choosing a career in the tech sector can be tricky. You wouldn’t want to choose something that’s getting obsolete. You would want to find a career option that’s in demand and will remain in demand for the coming years. With so many options available, figuring out which one to choose can also be overwhelming. One of those options is full-stack development.  Full-stack developers are experts who are familiar with both client-side and server-side programming. They perform the roles of front-end and back-end developers. While some may argue that they are no specialists, a talented full-stack developer wouldn’t have much trouble handling development projects.  But you might wonder, “What is full stack developer’s future scope?” We’ll answer that question in this article and help you understand how attractive this field is. Let’s dive in.  Check out our free courses to get an edge over the competition. Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript How Full Stack Development has Evolved You might think that full-stack development is a new term, but the concept has existed for a long time. Full-stack development has a fascinating history that goes back to the earliest days of programming. Knowing how much this field has evolved will let you get an idea of how much scope is there.  Since the beginning of software development, when there was no web or mobile programming, the role of full-stack developers has been present. In the early 80s, most of the software developers used to work alone and oversee the entire project from start to finish. Check out upGrad’s Full Stack Development Bootcamp (JS/MERN) There wasn’t much requirement of separate experts. Then the web came, and the need for specialists increased. As websites got more complex, the division between specialists also became distinct.  Things were this way in the 90s and remained this way until the mid-2000s. The term full-stack developer was coined much later, in the 2000s, when the web required the expertise of different expertise. Web applications required people to learn both client-side programming and server-side programming. And when people who studied both of these sectors entered the market, the term full stack developer arrived. Apart from that, tools and technologies that simplified the integration of client-side and server-side programming had entered the market. This helped the growth of full-stack developers.  Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses Full Stack Scope Now Nowadays, full-stack development is in huge demand. Companies need full stack developers because of several reasons. Full-stack developers can work with multiple technologies, and so, they can handle more aspects of a project than an average programmer. Check out upGrad’s Advanced Certification in Cyber Security They cut costs for companies because they can do the work of many specialists alone. A full-stack developer is familiar with many stacks, including the MEAN stack and the LAMP stack. Their vast knowledge of multiple areas equips them to handle the unique requirements of their projects.  The average salary for full-stack developers in India is about 6.3 LPA, and it goes up to 16 LPA for experts. Companies are willing to pay handsome salaries to full-stack developers because of their unique skill sets and abilities. As a full-stack developer, you’ll have to handle both the client-side and the server-side of the application you develop. Read a detailed article about the full stack developers salary in India based on various factors. Huge Demand and Steady Growth The future of full-stack development is attractive. It looks promising because of the steady growth in demand of these professionals. There are many reasons why the demand for full-stack developers is increasing and will keep rising in the coming years. Here are some of those reasons: Smaller Teams With a full-stack developer in the team, you can keep the team short. And smaller teams have many advantages over large ones. Even Jeff Bezos believes that a small team is better than a large staff. A large team requires more communication and more resources. A large team costs more than a small group as well. As they require more communication, the chances of facing problems of miscommunication are also higher in their cases.  A full-stack developer can easily handle the work of 2-3 developers because of his/her expertise. An excellent full-stack developer can handle the requirements of both a front-end developer and a back-end developer. Due to this reason, a company can keep the teams small, avoid miscommunication, and reduce the operating costs. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses upGrad’s Exclusive Digital Marketing Webinar for you – What’s new in Marketing? document.createElement('video'); https://cdn.upgrad.com/blog/rumi-ambastha.mp4   Adaptability Web development is a challenging field. A lot of factors are at play when you’re developing a new product. And the product’s requirements could change at any time. Maybe you found a new framework which can enhance productivity considerably. Or, maybe your team just got smaller because a member got fired. A full-stack developer is a preferred choice in such scenarios because he/she can adapt to these changes quickly.  Whether it’s taking on a new responsibility or making tweaks to the final product, full-stack developers can handle it all. Apart from that, as a full stack developer yourself, you wouldn’t have to worry about working on new projects that pose exciting challenges. After all, they are the “Jack of all Trades” of the sector.  Learn Software Development online from the World’s top Universities. Earn Executive PG Programs, Advanced Certificate Programs or Masters Programs to fast-track your career. New Technologies Development tools and software keep getting new updates for better performance. Even the programming languages get newer versions regularly to ensure they function better and cause less hassle. Most of the time, the new updates help with integrating different tools for enhanced productivity. Read: How to become a full stack developer? An average developer might have to put in a lot of effort to keep up with these new developments. He/she might not know how to approach the original subjects. On the other hand, a full stack developer has to learn the relations between different technologies beforehand. So keeping up with new updates and integrations is an easy task for him/her. Moreover, he/she would already be accustomed to learning new things about web development. That’s why they remain in huge demand. Read our Popular Articles related to Software Development Why Learn to Code? How Learn to Code? How to Install Specific Version of NPM Package? Types of Inheritance in C++ What Should You Know?   Conclusion You must’ve noticed how excellent the prospects are for full-stack developers. As companies are relying more and more on technology and the web, the demand for such experts is increasing. The full stack developer future scope is undoubtedly bright, and it’s the perfect time for anyone to learn this skill.  If you’re interested to learn more about full stack, check out upGrad & IIIT-B’s PG Diploma in Full-stack Software Development which is designed for working professionals and offers 500+ hours of rigorous training, 9+ projects and assignments, IIIT-B Alumni status, practical hands-on capstone projects & job assistance with top firms.
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by Rohit Sharma

26 Jan'20
25+Questions For Your Nagios Interview

6.89K+

25+Questions For Your Nagios Interview

Are you preparing for a DevOps interview? Then you should read these Nagios interview questions and answers.  Nagios is the most popular continuous monitoring software among companies. Companies rely on constant monitoring software to highlight errors and solve problems before they become significant issues. As a DevOps professional, recruiters would expect you to be familiar with all aspects of this powerful software. We’ve compiled a list of the most important Nagios interview questions and answers to help you prepare for your job interview. Feel free to share this list with others.  Check out our free courses to get an edge over the competition. What is Nagios? Nagios is a popular open-source solution that helps in monitoring systems, networks, and applications. It’s a standard DevOps tool, which tracks all the changes taking place in the subject. In case a technical fault arises, it can send alerts to the staff and make them aware of the issue as well. This way, the problem can be solved faster and earlier without it becoming a significant issue.  Nagios provides a centralized view of the complete infrastructure and vies detailed information on its status as well. You can also mention how it benefits organizations and how you can use it to solve the numerous problems related to the specific organization. Check out upGrad’s Advanced Certification in Cloud Computing Nagios helps in understanding where the infrastructure lacks and how you can upgrade it to overcome those problems. You can also mention how it automatically solves the issues detected. Nagios enables you to monitor the whole organization, its infrastructure, and its various processes.  This should answer the question. But you can add more points such as the advantages of using Nagios, and some other applications of Nagios, if required.  Check out upGrad’s Advanced Certification in Blockchain How Nagios helps DevOps Professionals? Nagios helps DevOps problems in tracking down issues and solving them in their early stages. This software solution overlooks every aspect of the infrastructure so it can spot an error and alert the technical team quickly. This way, DevOps professionals don’t have to worry about monitoring the systems for finding problems. They can rely on Nagios to spot the same.  Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses What are the features of Nagios? Nagios has many features.  – Its APIs enable it for monitoring various systems, infrastructures, and applications. – It has add-ons that make you aware of the aging infrastructure and help you in planning upgrades. – You have full access to its code as it is open-source software.  – Its reporting system is fast and agile. It gives you a record of all the alerts and their responses.  – You can view the entire infrastructure of your organization through Nagios while also seeing the detailed information about everything. – Nagios has a vast community of more than a million users. If you come across any problems or have any questions, you can ask them who’d be happy to help.  How does Nagios operate? You can give this explanation as to your answer: Nagios runs as a service on a server It runs plugins on the server which connect with hosts on the network You can see the detailed information of the connected host through its interface In case some issue arises, you would receive an email or another notification Nagios runs scripts at specific times and saves the results of those scripts If the results of running the scripts change, Nagios starts running other scripts  That is how Nagios operates.  What do you mean by ‘Plugins’ in Nagios? Plugins in Nagios are different scripts that check the status of a service or host. You’d run them from the command line. Nagios checks the results from its plugins to see the condition of the various hosts and services present in your network.  You can also explain why plugins are necessary for Nagios.  Nagios requires plugins to check the status of the numerous hosts and services present in a network. A plugin verifies the required host and sends the results of its check to Nagios. Nagios then processes the results and determines whether an action is needed or not.  In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses What is NRPE? NRPE enables you to run plugins on remote Unix and Linux machines. This way, Nagios can monitor local resources such as memory usage and CPU on remote components. Typically, these resources are not given to remote machines; that’s why you’d need to use NRPE.  You can also give an explanation of NRPE architecture for a more detailed answer.  NRPE contains two sections, the NRPE daemon, and the check_NRPE plugin. The former runs on a different computer while the latter remains in the local machine and has an SSL connection between the monitoring machine and the remote machine.  What is a Passive Check?  In Nagios, external processes initiate Passive checks. When they are completed, the results are sent to Nagios. Passive checks help in monitoring asynchronous services. Those services can’t be tracked without regular polling of their status. Passive checks also help Nagios in checking the status of hosts that are behind a firewall as they can’t be verified through a monitoring host.  What are the advantages of using Nagios? Nagios offers plenty of advantages to an organization.  It allows you to plan future upgrades for your existing infrastructure It ensures a technical error in your IT infrastructure has minimum impact It quickly alerts you of any new problems It allows you to monitor the entire system and infrastructure  It coordinates the responses of the technical staff It helps you find out how fast your team responds to technical problems It ensures that SLAs (Service-Level Agreements) of your organization are met What is Icinga? How is it related to Nagios? Icinga is another popular open-source software that helps in monitoring services. It was designed in 2009 to help Nagios, but it has become a separate software.  What is an Active Check? Nagios performs an Active check to poll a device or service for its status information on a scheduled basis.  Can you name a few databases which support Nagios? Many databases support Nagios. They are Oracle, Postgres, Microsoft SQL solutions, and MySQL.  What is Nagios XI? Nagios is the most trusted and most powerful monitoring software. It can help you in monitoring applications, network protocols, systems, services, and metrics. It provides you with all the advantages of Nagios (discussed above) and has a powerful performance.  Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript Is Nagios used to monitor window machines? Yes, Nagios is used to monitor window machines. You can do so by setting-up Nagios for monitoring the required window system and then add a separate server and host for performing the task.  What is OID Nagios? The Simple Network Management Protocol (aka SNMP) uses Object Identifiers for defining the Management Information Base.  What is the Nagios Network Analyzer? The network analyzer is a vital component of Nagios which checks the system for potential dangers. Its quick scan enables the admin to get the required data about the health of the system.  What are the benefits of using Nagios to monitor websites? Nagios can help you monitor websites too. It improves the website’s availability, helps you spot bugs, and you can enhance your site’s performance and avoid online security threats as well with the help of Nagios.  Is Nagios Object-oriented? If so, can you elaborate on what it means? Object-oriented means that you can produce object definitions in Nagios that are inherited from other objects. As Nagios is object-oriented, its relationship with its components remains simple without any intricate details.  Which protocols support Nagios? SMTP Monitoring, POP Monitoring, FTP Monitoring, IPMI Monitoring, DNS Monitoring, and LDAP Monitoring are some of the protocols Nagios supports.  Can you use Nagios for Cloud Monitoring? Yes, you can use Nagios for cloud monitoring. It is one of the most popular monitoring tools available in the market.  What are objects in Nagios? All elements related to the alerting logic and the monitoring process are objects in Nagios.  Name three virtualization platforms that support Nagios. Microsoft Virtual PC, Amazon EC2, and VMware are three of the most popular virtualization platforms supporting Nagios.  What are the object types in Nagios? Nagios has a variety of object types such as host groups, periods, services, hosts, contact, notifications, and commands.  What are the two-state types in Nagios? Soft states and hard states are the two primary state types in Nagios.  Which database format does Nagios support for storing data? Nagios supports the RRD database format for storing status data.  What are the sections of NDO utilities? NDO utilities include FILE2STOCK Utility, NDOMOD Event Broker Module, NDO2DB Daemon, and LOG2NDO Utility.  What are the default credentials in Nagios? The Username and Password are “nagiosadmin” in Nagios as default.  What language does Nagios core use? Nagios core uses PHP and CGI.  What are the required conditions for Nagios to check external commands? Nagios checks for external commands regularly according to the command_check_interval option. In addition to the regular checks, it also checks for external commands when an event handler is executed.  What are the differences between Passive and Active checks? It is one of the most popular Nagios interview questions, so we suggest you prepare the answer thoroughly.  The main difference between Active checks and Passive checks is that Nagios performs the former while an external application performs the latter.  Passive checks monitor services that are located behind a firewall or are asynchronous. Active tests can’t be done on those services or hosts even though Nagios performs them regularly.  How is Nagios related to DevOps? Continuous monitoring is a core component of DevOps and Nagios is a popular tool for the same.  Can you customize charts in Nagios? Yes, you can customize charts through a third-party tool such as Graphite or CACTI. What is the difference between soft and hard states in Nagios? To answer this question, you should define both of these states.  When the results of a host or service are not OK, but it has not been rechecked multiple times according to max_check_attempts, then the error is specified as a Soft error. When a host or service recovers from a Soft Error, it is called Soft Recovery. On the other hand, when the results of a host or service check are not OK even when they have been rechecked several times, according to max_check_attempts, the error is called Hard Error. Recovery from such a kind of error is called Hard Recovery.  upGrad’s Exclusive Software Development Webinar for you – SAAS Business – What is So Different? document.createElement('video'); https://cdn.upgrad.com/blog/mausmi-ambastha.mp4   Which three variables affect inheritance and recursion in Nagios? The three variables affecting recursion and inheritance are Name, Use, and Register. The name is a placeholder for other objects. Use specifies the parent object and Register can either have a value of 1 or 0. If the Register has a value of 1, it means it’s an actual object. If it has a value of 0, it means the object is only a template and isn’t a real object.  What is meant by State Stalking? Let us discuss what State Stalking is. State stalking helps in logging. With State Stalking, Nagios watches a particular service or host and log any changes it notices in the check results. You can also add that State Stalking is quite helpful in the analysis of logs. Without State Stalking, Nagios logs a check only when the state is changed between two checks.  What is Flap Detection in Nagios? When a host or service changes its state too frequently, it is called Flapping. Flapping can lead to many problems, which could, in turn, cause many recovery notifications to arise. Nagios checks if a service or host has started flapping during its status check.  Nagios checks for flapping. It does so by storing the results of the previous 21 checks of the specific service or host first. And it analyzes those results to see how frequent state changes occurred. It determines a percent state change value through that data and compares the same to flapping thresholds. When the percent state change is greater than the high threshold for flapping, the object is said to have started flapping. And when the percent state change is lower than the low threshold for flapping the object is said to have stopped flapping.  How would you explain the ‘Machine is Unreachable’ error? When Nagios fails in finding a path to a specific node, it shows this error. The node might be up, but because Nagios can’t access it, it shows the node as unreachable.  Final Thoughts We hope you found these Nagios interview questions helpful. Be sure to prepare all these questions thoroughly.  If you’re interested to learn more about Nagios, check out upGrad & IIIT-B’s PG Diploma in Full-stack Software Development which is designed for working professionals and offers 500+ hours of rigorous training, 9+ projects, and assignments, IIIT-B Alumni status, practical hands-on capstone projects & job assistance with top firms.  
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by Arjun Mathur

30 Jan'20
Continuous Delivery vs. Continuous Deployment: Difference Between

6.17K+

Continuous Delivery vs. Continuous Deployment: Difference Between

Knowing the difference between continuous delivery vs continuous deployment is paramount in today’s rapidly progressing world. That is because your users should be able to update the software without much hassle.  It is something that you are aware of through your smartphone, laptop, or computer software. Software updates for a wide range of applications are a regular occurrence. Without them happening, developments cannot take place.  Check out our free courses to get an edge over the competition. So, what can you do about it? In this internet era, you should be able to meet your user’s requirements in a matter of time. When you rectify errors or issues quickly, you can retain your clients. At the same time, when you find it challenging to do so, it can cause drowning profits.  So, when you opt for the usual slow and obsolete process of finding, analyzing, and planning methods, you are well out of the market. You have lost the plot altogether. To avoid being left out in the lurch, what you require is agile development.  Check out upGrad’s Advanced Certification in Cyber Security  Opt for agile development Agile development is the process or framework where you can test, plan, and eventually implement your ideas. The best part is that you can do it immediately. Instant results are the order of the day.  Those businesses and companies that have embedded agile development into their processing plans stand to gain from it. When you can achieve continuous delivery as well as constant deployment in your solution delivery pipeline, your firm can release the updates efficiently.  For our readers, who are not aware of the difference between continuous delivery and continuous deployment, then we will try and clarify through this post. Not to mention, you will also learn how they fit into an agile environment.  When you want to understand both continuous delivery and continuous deployment, then you must first understand, continuous integration.  Check out upGrad’s Advanced Certification in Cloud Computing  It is an essential element for agile practice.  An Agile Developer knows the significance of implementing this process because it gives them the ability to manage smaller components. This way, they can design quality software. For agile concepts, all the teams know what is going on, unlike the waterfall concept.  Explore our Popular Software Engineering Courses Master of Science in Computer Science from LJMU & IIITB Caltech CTME Cybersecurity Certificate Program Full Stack Development Bootcamp PG Program in Blockchain Executive PG Program in Full Stack Development View All our Courses Below Software Engineering Courses Developers must use deployment automation tool        That is why developers must consider using automation of continuous deployment at the development stage itself. Solutions should be given to ensure that continuous integration and continuous delivery are smoothly handled through a consumption-based model. What is continuous integration? Continuous integration is a process where, several methodologies are used from several sources, automatically to integrate the code for designing and testing purposes. As a DevOps Developer, when your design code can pass the test, then it is deployed automatically.  Further testing is then conducted on your code like manual exploratory test and load test. You would be surprised to know that the process can take several days. It entirely depends on the requirements.  What is continuous delivery? Continuous delivery enables you to design a high-quality version of your code. This classic version helps you to decide when you want to release your software for your clients, based on the feedback. In most cases, the timing of the release matters depending on the market condition.  Continuous delivery vs. continuous deployment It is the main difference between continuous delivery vs continuous deployment. Continuous deployment is the process where the software to be released undergoes an automated pipeline. Developers need not worry about the release, but rather ensure that the code developed, is regularly tested, updated, and then released. More importantly, it must work fine from the client’s end.  The continuous delivery consists of a time lag before the release of the software. The product gets reviewed, and changes, if any, is done before the release. Continuous deployment involves automated testing throughout the entire process until the release of the product.  Explore Our Software Development Free Courses Fundamentals of Cloud Computing JavaScript Basics from the scratch Data Structures and Algorithms Blockchain Technology React for Beginners Core Java Basics Java Node.js for Beginners Advanced JavaScript How can you consolidate delivery and deployment to attain common goals? It is when some developers get tempted to think that continuous deployment may be advantageous for the software. It depends on the CI/CD practices implemented in your organization.  However, there are some constraints that you might want to beware of before making use of continuous deployment. Market conditions and regulatory compliances, usually restrict IT firms from making use of continuous deployment. The levels of the DevOps concepts implemented in an IT firm also dramatically influences the usage of continuous deployment.  Continuous delivery requires manual code changes, and that can delay in the deadline for deploying the code.  But, there are some benefits to using it. IT firms may want to consider using continuous delivery because of the convenience. It enables IT firms to have a competitive advantage for deploying the code, ably supported by human intelligence.  Developers can come up with many new features that can be designed and ready for implementation. It enables them to develop robust and resilient systems. What this does is, reduces the production costs, and allows developers to improve the quality of the product.  But, continuous delivery and continuous deployment may not be that relevant in some areas of work. You may not require a deployment phase when contributing to a library or designing an artifact. In-Demand Software Development Skills JavaScript Courses Core Java Courses Data Structures Courses Node.js Courses SQL Courses Full stack development Courses NFT Courses DevOps Courses Big Data Courses React.js Courses Cyber Security Courses Cloud Computing Courses Database Design Courses Python Courses Cryptocurrency Courses Likewise, many web applications do not have to come up with a design and deploy phases. These days, there is a new development for designing high-end tools for application release that can effectively manage software releases. Few of them include: Packaging of the applications  The version of the release  When updating the database  Managing the configuration of the server  Rollback and roll forward  Auditing and access for security purposes To summarise, the main difference between continuous delivery vs continuous deployment would be that continuous delivery is the ability to release a version on any platform. On the other hand, continuous deployment is your ability to deploy the versions continuously.  Both the concepts need a framework, where you can work on small, but effective changes that can be implemented immediately in the market. It would help if you learned how your updates had affected the users, in a good and bad way.  You will need to communicate with your clients to achieve what you intend to by finding out how it helped or did not help them. However, to make that, you need to bring value to your users.  upGrad’s Exclusive Software Development Webinar for you – SAAS Business – What is So Different? document.createElement('video'); https://cdn.upgrad.com/blog/mausmi-ambastha.mp4   Do you want to learn more? If you are keen on developing your DevOps skills and learning more about the continuous delivery vs continuous deployment, then we would recommend you take up courses taught from an online higher education platform.  Only a handful of these online education platforms have tie-ups and partnerships with universities like IIT Madras, IIIT-B, MICA, NMIMS, and Cambridge Judge Business School Executive Education. When they certify you, it elevates your knowledge and enables you to stand out from the crowd. The above-mentioned reasons are why an online course in full-stack software development can kickstart your career in tech, especially if you are looking to switch lanes.
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by Rohit Sharma

05 Feb'20