core data ios swift interview questions
One wrong answer during your first interviews can determine if you get the job, or just a “thank you for participate”. I am an IOS developer, a self-taught one, a lot of curiosity and passion for coding. In this case, your class must conform to NSCoding for the transformation to occur. These classes/objects are the main building blocks of the core data stack. Core Data has caching built-in. Welcome to iosdose Register Now! In iOS, Apple provides UIView as a base class for all _View_s, UIViewController is provided to support the Controller which can listen to events in a View and update the View when data changes. Private Queue specifies the context that will be associated with a private dispatch queue instead of the main queue. Transformable properties like this are very easy to use because you read and write to them as normal, while the encryption/decryption goes on behind the scenes. How can I encrypt Core-Data contents on an iPhone? We can do multithreading in core data with multiple contexts, example background context for long-running tasks (batch inserting/fetching/updating) and update UI on the main thread. A Managed object model allows core data to map from records in a persistent store to managed objects that you use in your Application. “When you retrieve an object from an NSManagedObjectContext (MOC) you can’t tell (in the normal course of its use) whether it’s a fault or a realized object”. The Core Data framework excels at managing complex object graphs. The big day is coming up. In-Memory Persistent Store The central feature of Core Data is the ability to store data in a persistent store that allows data to stick around permanently, ie after the app is no longer running. An app stays in this state briefly as it transitions to a different state. For save or retrieval of large data because of it’s abilities to handle the less processing speed of the device. As the name of the NSManagedObjectContextWillSaveNotification notification suggests, this notification is posted before a save operation is performed. Microsoft Power BI SQL Tableau Business Analysis Business Intelligence Data Analysis MySQL Data Modeling DAX. Concurrency is the ability to work with the data on more than one queue at the same time. The technique is known as Uniquing. Core Data is one of the most popula r frameworks provided by Apple for iOS and macOS apps. Swift Interview Questions: IOS swift is the latest programming language. ... With more than 170 iOS 11 & Swift 4 interview questions, the 170+ iOS 11 & Swift 4 Interview Questions course is here to help you. There has never been a better time to become an iOS developer. There are two concurrency types a managed object context can use:-. ... Browse other questions tagged ios swift uitableview core-data or ask your own question. Data model objects are app specific objects and store app’s content. Persistent Store Coordinator is actually the instances of “NSPersistentStoreCoordinator” class.. The managed object context performing the save operation posts an NSManagedObjectContextDidSaveNotification notification after successfully saving its changes. It's the Model in the Model-View-Controller pattern that permeates the iOS SDK. In computer science, in an object-oriented program, groups of objects form a network through their relationships with each other—either through a direct reference to another object or through a chain of intermediate references. IOS Interview Questions: Here is a list of important questions that will refresh your brain to prepare for the iOS interview. Core Data is a framework that is used to manage model layer objects. What is NSPersistentStoreCoordinator? Swift is only four years old, but it’s already become the default language for iOS development. Identifiers contain the information needed to exactly describe an object in a persistent store (like the primary key in the database), although the detailed information is not exposed. 19. 8. The image Data is Converted to and From an NSData Instance that contains the image’s PNG Representation .this is all handled transparently for you by a custom NSValueTransformer. But following US Navy Seals motto “Two is one and one is none”let’s go thr… ... use Swift along with Objective-C for now and move to pure Swift down the road in several years when it and the ecosystem of libraries around it matures enough. Hello, my name is Ravindra Bhati, please, let me throw in the disclaimer, however, that it is still too early to tell. When we talk about persistent data, people probably think of database. Interview Questions And Answers - Core Data, Collection of interview questions for core data. They are calculated at runtime, usually on the basis of other property Values. To give a super boost to your career, below is a list of regularly posted iOS interview questions which helps in passing the IOS job interview. In OS X v10.7 and later and iOS v5.0 and later, when you create a context you can specify the concurrency pattern with which you will use it using initWithConcurrencyType:. Thanks for reading. Core Data ensures that — in a given managed object context — an entry in a persistent store is associated with only one managed object. The questions will give you an idea about the pattern and the right way to answer the questions that may be thrown your way during the interview Swift is only four years old, but it’s already become the default language for iOS development. So, You Want to Scan a Billion Files in a Day. The different iOS application states are: Not running state: when the app has not been launched or was running but was terminated by the system. Here is the list of most frequently asked iOS Interview Questions and Answers in technical interviews. Is Core Data == SQLite or some wrapper? ♥♥️♥️When you retrieve an object from an NSManagedObjectContext (MOC) you can’t tell (in the normal course of its use) whether it’s a fault or a realized object*** — Yes we can, use –isFault. Core Data can then manage object instances at runtime to provide the following features. ❍ The NSManagedObjectModel object knows about the data model by loading one or more data model files during its initialization. Depending on the encryption used, I would even expect that the on-disk data accesses for loading each entity would be slower than the decryption process for the properties, so you won’t see that much of a performance penalty when accessing the properties. Interview Questions Interactive Review Test your Swift Find a Job Store. https://harsivo.com/Here i have covered 15 iOS interview questions and answers. The Core Data framework takes care of managing the life cycle of the objects in the object graph. In a database, an attribute corresponds to a particular field in a table. The framework completely encapsulates the “external” information and presents a clean object oriented interface. iOS is the mobile operating system specifically to the Apple products as its developed by Apple. Core data is an object graph manager which also has the ability to persist object graphs to the persistent store on a disk. In this case, you must have a custom transformer class that knows how to perform the transformation. An attribute is a piece of information attached to a particular entity. A fault will be converted into a realized object (“fired”) automatically by the Core Data framework in most cases when it is necessary to do so. In Swift, the classes are not inherited from the base class and the classes that you define without specifying its superclass, automatically becomes the base-class. Here a list of frequently asked Swift interview questions and answers for beginners. Though SQLitedatabase is the default persistent store for Core Data on iPhone, Core Data is not a relational database. 14. This type is what the main context (core data stack.mainContext) uses. This is the type of queue you just used to move the export operation off of the main queue so it would no longer interfere with the UI. or want to know something more about it. Swift is a fantastic way to develop software, it is an interactive programing language which is fast, safe, and friendly to new programs. I hope you will like this. Objects are linked to each other by one object either owning or containing anoth… Do you have experience in swift/java?Having hands-on experience in iOS development, Automation and Manual testing will be helpful to gain edge in career path. Here are three apps that can help. - 9magnets/iOS-Developer-and-Designer-Interview-Questions What is the minimum necessary classes and the relationship between them? 33. 17. You can treat Core Data as a framework to save, track, modify and filter the data within iOS apps, however, Core Data is not a Database. Managed object context can contain one or more managed object model instances. Following are the list of some basic Swift interview questions … Core data is used to manage the model layer object in our application. Here are the top 19 sample iOS interview questions and their answers. No, NSManagedObject instances are not intended to be passed between queues. ALLInterview.com. As you will see during this or future posts, English it’s not my first language, so please if you are sensitive to grammatical crimes this is the best time for you to response on that, I ‘ll Correct as Soon. What is Persistence store coordinator 3. But UIImage can be converted to and from NSData. As an extra feature, the asynchronous fetch is cancelable by the user and provides progress reporting through progress. A small guide to help those looking to hire a developer or designer for iOS work. What is Latest Version of iOS & Swift ? Can we do Multithreading with core data? Contexts and their managed objects must only be accessed from the correct queue. ❍ it contains information about the models or entities of the object graph, what attributes they have, and how they relate to one another. How to Save custom class into Core data? Apps can also use document objects to manage some or all of their data model objects. Additionally, it will allow the decryption to be done lazily, rather than all upfront, so your application will load much faster. In Core Data, relationships between two entities are called to-one relationships, while those between one and many entities are called to-many relationships. So, to ease the stress you did some prep work- completed the homework on the company you are interviewing with, stalked the hiring manager and half of the engineering team at the company of your choice on linkedin & github, you brushed up on some of the skills and knowledge you haven’t used in a while- you are ready to go. 32. To fetch the data asynchronously in a background queue, Core Data provides the object NSAsynchronousFetchRequest. That’s right. As Swift has evolved to version 5.0, it’s turned into a complex and powerful language embracing both object-oriented and functional paradigms. Swift and Objective-C iOS isn’t just about Swift. Most of the time core data uses in-memory objects (managed object context). It is memory efficient technique used with some of the classes like DateFormatter, Calendar also. Core Data is one of the most popular frameworks provided by Apple for iOS and macOS apps. It also suits a business requirement where you have a model with it’s attributes. According to the Core Data concurrency rule, each thread must have its own managed object context. Menu iOS Interview Questions for Senior Developers in 2017 17 September 2017 on iOS, Interviews, Interview Questions, Swift. An NSManagedObject is a run-time representation of a Core Data entity. Core Data consist of following stack objects: 5. ... Now for the important part: go to the the iOS simulator, then choose the Hardware menu and Erase All Content And Settings. Importantly though, when unit testing, you don’t want to use that persistent data. core data is ORM(Object graph model) which create a layer between the database and the UI. It is ac… For Example:- I provide code Below that lets you store UIImages as An Attribute within core data. When working with core data it is recommended to use a lazy keyword for lazy initialization of persistent container. What is ManagedObject 2. We need NSManagedObject, NSManagedObjectContext and a Persistence store container. A. Each managed object context is backed by a persistent store coordinator. Clean way to save observers on Core Data objects? Core Data is a framework that manages an object graph. Support for Swift: Xcode 6 explicitly supports the Swift code, it is very simple and easy to make a brand new app using 100% swift code to existing frameworks. These sample questions are framed by experts from Intellipaat who train for the iOS Training Course to give you an idea of the type of questions that are asked in interviews. This is an update of my two-year-old blog post on iOS interview questions.I revised it after doing extensive research while working on my book on the topic: The iOS Interview Guide.