#couchdb

[tutorialwithexample]

Unraveling Apache CouchDB: The Ultimate Guide for Database Enthusiasts

In the realm of NoSQL databases, Apache CouchDB stands out as a versatile and scalable option. This Apache CouchDB tutorial aims to demystify its intricacies, making it accessible to both beginners and seasoned developers.

Getting Started with Apache CouchDB

Begin your journey by installing and setting up Apache CouchDB. This straightforward process lays the foundation for efficient database management.

Mastering Basic Operations

Learn the fundamental operations like creating, updating, and deleting documents. Explore how CouchDB's unique approach to document storage enhances flexibility and performance.

Advanced Querying Techniques

Delve deeper into CouchDB's querying capabilities. Uncover methods for complex queries, including MapReduce functions, that enable you to extract precisely the data you need.

Replication and Scalability

Discover how to replicate databases for redundancy and distributed setups. Harness the power of CouchDB's multi-master replication to ensure data integrity and availability.

Optimizing Performance

Fine-tune your CouchDB instance for optimal performance. Explore techniques for indexing, caching, and load balancing to keep your database running smoothly.

With this tutorial, you'll gain the expertise needed to harness the full potential of Apache CouchDB. Whether you're building a small-scale application or a large-scale system, CouchDB's flexibility and scalability will be at your fingertips.

For a more detailed guide on Apache CouchDB, visit Tutorial and Example.

Remember, practice makes perfect. Dive in, experiment, and unleash the power of Apache CouchDB!

[jtpoint]

Unlock the power of Apache CouchDB with our in-depth tutorial. From setup to advanced queries, master database management with step-by-step guidance and practical examples. Start learning today!

[amwult]

1pm: i am going to bed early tonight 1am: couchdb deployment

[aitoolswhitehattoolbox]

Senior Backend Developer

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[dssd34526]

Web Development Course In Rohini

Web development is the process of building and maintaining websites or web applications. It involves a wide range of tasks, from web design and content creation to server-side programming and database management. With the internet becoming an integral part of daily life and business, web development has evolved significantly, expanding into multiple domains, each with its unique set of challenges and tools.

1. The Basics of Web Development

At its core,  Web Development Course In Rohini focuses on the creation and management of websites that are accessible via the internet. A website is typically made up of three main components:

Frontend (Client-Side): This is the part of the website users interact with directly. It involves everything the user experiences visually—design, layout, navigation, and interactivity.

Backend (Server-Side): This part is responsible for the website’s functionality behind the scenes. It handles server configurations, database interactions, user authentication, and business logic.

Database: Websites often need to store data, whether it’s user accounts, product information, or any other type of content. A database organizes and retrieves this data when needed.

2. Frontend Development

Frontend development is the creation of the user-facing part of a website. It includes everything that the user sees and interacts with. To build the frontend, developers use a combination of:

HTML (HyperText Markup Language): HTML is the foundational language used to structure content on the web. It defines the basic layout of a webpage, such as headings, paragraphs, images, and links.

CSS (Cascading Style Sheets): CSS is responsible for the design and appearance of a website. It controls aspects like colors, fonts, spacing, and positioning of elements on the page.

JavaScript: JavaScript adds interactivity and dynamic behavior to a website. It can be used to handle user events (like clicks or form submissions), create animations, validate data, and even interact with remote servers.

Modern frontend development often relies on frameworks and libraries such as React, Angular, and Vue.js to streamline the development process and improve the user experience. These tools allow developers to create complex user interfaces (UIs) more efficiently by providing pre-built components and patterns.

3. Backend Development

Backend development refers to the server-side of web development, responsible for processing and managing data and serving it to the frontend. It ensures that everything behind the scenes operates smoothly. Backend developers work with:

Programming Languages: Several programming languages are used for backend development. The most common are JavaScript (Node.js), Python, Ruby, PHP, Java, and C#. These languages allow developers to write scripts that handle logic, process data, and manage server requests.

Web Frameworks: Web frameworks simplify the development of backend applications by providing a structured approach and pre-built components. Some popular backend frameworks include Django (Python), Express (Node.js), Ruby on Rails (Ruby), and Laravel (PHP).

Databases: Databases are used to store and manage data on the server. There are two primary types of databases:

Relational Databases (RDBMS): These use tables to store data and SQL (Structured Query Language) to query it. Popular RDBMSs include MySQL, PostgreSQL, and SQLite.

NoSQL Databases: These databases are more flexible and can handle unstructured or semi-structured data. MongoDB and CouchDB are examples of NoSQL databases.

Server Management: Backend developers often work with server management tools and services to deploy and maintain the application. This can involve cloud services like Amazon Web Services (AWS), Google Cloud, and Microsoft Azure, or self-hosted servers using technologies like Docker and Kubernetes.

4. Full-Stack Development

A full-stack developer is one who works with both frontend and backend technologies. Full-stack developers are proficient in both client-side and server-side development, enabling them to build an entire web application from start to finish. They often use a combination of tools and frameworks that span the full development stack, such as:

Frontend Tools: React, Angular, Vue.js, HTML, CSS, JavaScript.

Backend Tools: Node.js, Express, Django, Ruby on Rails.

Databases: MySQL, MongoDB, PostgreSQL.

Full-stack developers must understand how both the frontend and backend interact with each other, ensuring seamless communication between the two. They also need to be familiar with DevOps practices, which involve managing code deployments, automating workflows, and maintaining the application’s infrastructure.

5. Web Development Trends

Web development is constantly evolving, and several trends have emerged in recent years that have significantly impacted the way websites and applications are built:

Progressive Web Apps (PWAs): PWAs are web applications that function like native mobile apps, offering offline capabilities, push notifications, and better performance. They are designed to provide a seamless experience across devices, including smartphones, tablets, and desktops.

Single-Page Applications (SPAs): SPAs load a single HTML page and dynamically update content as users interact with the site. This leads to faster load times and a more app-like experience. Frameworks like React and Angular are often used to build SPAs.

Responsive Web Design: With the increasing use of mobile devices, responsive web design has become essential. It ensures that websites adjust their layout and content according to the screen size, improving user experience across all devices.

Serverless Architecture: Serverless computing allows developers to build and run applications without managing the infrastructure. Services like AWS Lambda and Google Cloud Functions handle scaling, server management, and hosting, reducing the operational complexity for developers.

API-First Development: APIs (Application Programming Interfaces) allow different systems to communicate with each other. API-first development focuses on building APIs before creating the frontend or backend, ensuring better integration and scalability for web applications.

Web Accessibility (a11y): Making websites accessible to users with disabilities is critical. Web developers must follow accessibility guidelines (WCAG) to ensure that websites are usable by everyone, including those with visual, auditory, or motor impairments.

6. The Importance of User Experience (UX) and User Interface (UI) Design

A successful website is not just about functional code—it's about the user’s experience. UX and UI design are critical components of web development. UX focuses on how a website or app feels, while UI is concerned with how it looks. Both are important because they directly impact how users interact with the website and whether they return.

Good UX/UI design principles include:

Simplicity: Avoid cluttered interfaces. A clean, intuitive design enhances usability.

Consistency: Use consistent layouts, color schemes, and fonts to guide users.

Navigation: Ensure the site’s navigation is intuitive and easy to use.

Performance: Optimizing speed is crucial. Websites should load quickly and perform smoothly.

7. Web Development Tools and Technologies

Web developers use a variety of tools and technologies to improve their workflow and build more efficient, high-quality applications:

Version Control Systems: Tools like Git and platforms like GitHub or GitLab allow developers to track changes in their code, collaborate with others, and manage different versions of their projects.

Code Editors and IDEs: Text editors such as VS Code, Sublime Text, or Atom are commonly used by developers to write and edit code. Integrated Development Environments (IDEs) like JetBrains' IntelliJ IDEA or PyCharm offer more advanced features, including code completion, debugging, and testing support.

Build Tools: Tools like Webpack, Gulp, and Grunt help automate tasks like bundling assets, compiling code, and minifying files, making development faster and more efficient.

Testing Frameworks: Tools like Jest, Mocha, and Cypress allow developers to write unit and integration tests, ensuring that the code works as expected and reducing the risk of bugs.

Conclusion

Web development is a dynamic and essential field that continues to grow and evolve. With the increasing reliance on the internet, the demand for skilled web developers is higher than ever. By mastering both frontend and backend technologies, understanding current trends, and prioritizing user experience, developers can create functional, scalable, and user-friendly websites that meet the needs of businesses and users alike. As technology advances, the role of web developers will continue to expand, opening up new opportunities for innovation and creativity in the digital space.

[chocolatedetectivehottub]

Web Development,

Web Development,

Web Development: A Comprehensive Guide

Introduction to Web Development

Web development is the process of building and maintaining websites and web applications. It involves a combination of coding, design, and content creation that works together to make websites functional and user-friendly. Whether it's a simple personal blog or a complex e-commerce site, web development is a critical part of our online experience. It can be broken down into three main areas: frontend development, backend development, and full-stack development.

Frontend Development

Frontend development refers to everything that users interact with on the website. This includes the layout, design, structure, and behavior of a site. It’s all about creating an engaging and responsive user interface.

Languages Used:

HTML (HyperText Markup Language): HTML is the backbone of any website, providing the structure and content.

CSS (Cascading Style Sheets): CSS is used for styling the website, determining its colors, fonts, spacing, and overall look.

JavaScript: JavaScript is a programming language that allows developers to add interactive elements like buttons, forms, sliders, and animations.

Frontend Frameworks and Libraries:

React: A JavaScript library for building user interfaces, particularly single-page applications.

Angular: A framework that helps developers build dynamic web applications using TypeScript.

Vue.js: A progressive framework for building UIs that focuses on ease of integration with other libraries and projects.

Responsive Design:

Ensuring that a website looks good on all devices, from desktop computers to smartphones, is a key element of frontend development. Responsive design uses flexible grids, images, and CSS media queries to create websites that adapt to the user’s screen size.

Backend Development

Backend development is all about the server-side of a website. It involves creating the logic, databases, and server-side functionality that make the frontend interactive. It ensures that when a user clicks on a link or submits a form, the correct data is retrieved, stored, or processed.

Languages Used:

PHP: A widely-used open-source language that powers many content management systems (CMS) like WordPress.

Python: Known for its simplicity and versatility, Python is used in web development frameworks like Django and Flask.

Ruby: Ruby on Rails is a popular backend framework known for its speed and simplicity.

Java: Java is often used for large-scale, enterprise-level applications.

Node.js: A runtime environment that allows developers to use JavaScript on the server-side as well.

Databases:

SQL Databases: Structured Query Language (SQL) is used to manage and manipulate data in relational databases like MySQL, PostgreSQL, and SQLite.

NoSQL Databases: Non-relational databases like MongoDB, CouchDB, and Firebase are used to handle unstructured or semi-structured data.

Web Servers:

Web servers like Apache and Nginx handle requests from users' browsers and serve web pages and resources from the server to the client.

Full-Stack Development

Full-stack development refers to developers who work on both the frontend and backend of a website. These developers are skilled in both client-side and server-side technologies, making them versatile and capable of building entire websites from start to finish.

Full-stack developers typically use combinations of technologies like:

Frontend: HTML, CSS, JavaScript, and frameworks like React, Angular, or Vue.js.

Backend: Languages such as Node.js, Python, Ruby, or PHP, and databases like MySQL, MongoDB, or PostgreSQL.

DevOps: Full-stack developers may also be involved in deployment, using tools like Docker, Kubernetes, or cloud services like AWS and Azure.

Web Development Tools

Code Editors:

Tools like Visual Studio Code, Sublime Text, and Atom help developers write and edit code efficiently.

Version Control:

Git: A distributed version control system that tracks changes to code. GitHub and GitLab are popular platforms that host repositories.

Development Environments:

Local environments like XAMPP, WAMP, and Docker allow developers to run web applications on their local machines before deploying them live.

APIs (Application Programming Interfaces):

APIs allow different applications to communicate with each other. They are essential for integrating third-party services, such as payment gateways, social media sharing, and weather data.

The Future of Web Development

As technology evolves, so does web development. The increasing use of artificial intelligence, machine learning, and blockchain is creating new opportunities for developers. Additionally, web development is becoming more modular, with microservices and serverless architectures allowing for faster and more scalable applications.

Furthermore, the demand for Progressive Web Apps (PWAs) and Single-Page Applications (SPAs) is rising, as these apps provide seamless user experiences across multiple devices without the need for full page reloads.

Conclusion

Web development is a dynamic and essential field that powers the internet as we know it. Whether you’re interested in the creative aspects of frontend development or the logic-driven challenges of backend development, there’s a vast world of opportunities in this field. As the web continues to evolve, so too will the tools and technologies developers use to build innovative and user-centric experiences.

4o mini

[fromdevcom]

Spring in Practice By By Willie Wheeler, John Wheeler, and Joshua White Among the tasks a content management system (CMS) must support are the authoring, editing and deployment of content by non-technical users. Examples include articles (news, reviews), announcements, press releases, product descriptions and course materials. In this article, based on chapter 12 of Spring in Practice, the authors build an article repository using Jackrabbit, JCR and Spring Modules JCR. Prerequisites None. Previous experience with JCR and Jackrabbit would be helpful. Key technologies JCR 2.0 (JSR 283), Jackrabbit 2.x, Spring Modules JCR Background Our first order of business is to establish a place to store our content, so let’s start with that. In subsequent recipes we’ll build on top of this early foundation. Problem Build an article repository supporting article import and retrieval. Future plans are to support more advanced capabilities such as article authoring, versioning, and workflows involving fine-grained access control. Solution While it’s often fine to use files or databases for content storage, sometimes you must support advanced content- related operations such as fine-grained access control, author-based versioning, content observation (for example, “watches”), advanced querying, and locking. A content repository builds upon a persistent store by adding direct support for such operations. We’ll use a JSR 283 content repository to store and deliver our articles. JSR 283, better known as the Java Content Repository (JCR) 2.0 specification1, defines a standard architecture and API for accessing content repositories. We’ll use the open source Apache Jackrabbit2.x JCR reference implementation at http://jackrabbit.apache.org/. Do we really need JCR just to import and retrieve articles? No. If all we need is the ability to import and deliver articles, JCR is overkill. We’re assuming for the sake of discussion, however, that you’re treating the minimal delivery capability we establish here as a basis upon which to build more advanced features. Given that assumption, it makes sense to build JCR in from the beginning as it’s not especially difficult to do. If you know that you don’t need anything advanced, you might consider using a traditional relational database backend or even a NoSQL document repository such as CouchDB or MongoDB. Either of those options is probably more straightforward than JCR. For more information on JCR, please see the Jackrabbit website above or check out the JSR 283 home page at http://jcp.org/en/jsr/detail?id=283. Java Content Repository basics The JCR specification aims to provide a standard API for accessing content repositories. According to the JSR 283 home page: A content repository is a high-level information management system that is a superset of traditional data repositories. A content repository implements content services such as: author based versioning, full textual searching, fine grained access control, content categorization and content event monitoring. It is these content services that differentiate a content repository from a Data Repository. Architecturally, so-called content applications (such as a content authoring system, a CMS, and so on) involve the three layers shown figure 1. Figure 1 JCR application architecture. Content apps make calls against the standardized JCR API, and repository vendors provide compliant implementations. The uppermost layer contains the content applications themselves. These might be CMS apps that content developers use to create and manage content, or they might be content delivery apps that content consumers use. This app layer interacts with the content repository2 (for example, Jackrabbit) through the JCR API, which offers some key benefits: The API specifies capabilities that repository vendors either must or should provide. It allows content apps to insulate themselves from implementation specifics by coding against a standard JCR API instead of a proprietary repository-specific API.

Apps can, of course, take advantage of vendor-specific features, but, to the extent that apps limit such excursions, it will be easier to avoid vendor lock-in. The content repository itself is organized as a tree of nodes. Each node can have any number of associated properties. We can represent individual articles and pages as nodes, for instance, and article and page metadata as properties. That’s a quick JCR overview, but it describes the basic idea. Let’s do a quick overview of our article repository, and after that we’ll start on the code. Article repository overview At the highest level, we can distinguish article development (for example, authoring, version control, editing, packaging) from article delivery. Our focus in this recipe is article delivery and, specifically, the ability to import an “article package” (assets plus metadata) into a runtime repository and deliver it to readers. Obviously, there has to be a way to do the development too, but here we’ll assume that the author uses his favorite text editor, version control system, and ZIP tool.4 In other words, development is outside the scope of this writing. See figure 2 for an overview of this simple article management architecture. Figure 2 An article CMS architecture with the bare essentials. Our development environment has authoring, version control and a packager. Our runtime environment supports importing article packages (e.g., article content, assets and metadata) and delivering it to end users. In this recipe, JCR is our runtime article repository. That’s our repository overview. Now it’s time for some specifics. As a first step, we’ll set up a Jackrabbit repository to serve as the foundation for our article delivery engine. Set up the Jackrabbit content repository If you’re already knowledgeable about Jackrabbit, feel free to configure it as you wish. Otherwise, Spring in Practice’s code download has a sample repository.xml Jackrabbit configuration file. (It’s in the sample_conf folder.) Just create a fresh directory somewhere on your filesystem and drop the repository.xml configuration file right in there. You shouldn’t need to change anything in the configuration if you’re just trying to get something quick and dirty to work. There isn’t anything we need to start up. Eventually we will point the app at the directory you just created. Our app, on startup, will create an embedded Jackrabbit instance against your directory. To model our articles we’re going to need a couple of domain objects: articles and pages. That’s the topic of our next discussion. Build the domain objects Our articles include metadata and pages. The listing below shows an abbreviated version of our basic article domain object covering the key parts; please see the code download for the full class. Listing 1 Article.java, a simple domain object for articles package com.springinpractice.ch12.model; import java.util.ArrayList; import java.util.Date; import java.util.List; public class Article { private String id; private String title; private String author; private Date publishDate; private String description; private String keywords; private List pages = new ArrayList(); public String getId() return id; public void setId(String id) this.id = id; public String getTitle() return title; public void setTitle(String title) this.title = title; ... other getters and setters ... There shouldn’t be anything too surprising about the article above. We don’t need any annotations for right now. It’s just a pure POJO. We’re going to need a page domain object as well. It’s even simpler as we see in the listing below Listing 2 Page.java, a page domain object package com.springinpractice.ch12.model; public class Page private String content; public String getContent() return content; public void setContent(String content) this.content = content; It would probably be a nice to add a title to our page domain object, but this is good enough for our current purpose.

Next, we want to look at the data access layer, which provides a domain-friendly API into the repository. Build the data access layer Even though we’re using Jackrabbit instead of using the Hibernate backend from other chapters, we can still use the Dao abstraction we’ve been using. Figure 3 is a class diagram for our DAO interfaces and class. Our Hibernate DAOs had an AbstractHbnDao to factor some of the code common to all Hibernate-backed DAOs. In the current case, we haven’t created the analogous AbstractJcrDao because we have only a single JCR DAO. If we had more, however, it would make sense to do the same thing. We’re going to want a couple of extra operations on our ArticleDao, as the listing below shows. Listing 3 ArticleDao.java, a data access object interface for articles package com.springinpractice.ch12.dao; import com.springinpractice.ch12.model.Article; import com.springinpractice.dao.Dao; public interface ArticleDao extends Dao void createOrUpdate(Article article); #1 Article getPage(String articleId, int pageNumber); #2 #1 Saves using a known ID #2 Gets article with page hydrated Our articles have preset IDs (as opposed to being autogenerated following a save(, so our createOrUpdate() method (#1) makes it convenient to save an article using a known article ID. The getPage() method (#2) supports displaying a single page (1-indexed). It returns an article with the page in question eagerly loaded so we can display it. The other pages have placeholder objects just to ensure that the page count is correct. The following listing provides our JCR-based implementation of the ArticleDao. Listing 4 JcrArticleDao.java, a JCR-based DAO implementation package com.springinpractice.ch12.dao.jcr; import static org.springframework.util.Assert.notNull; import java.io.IOException; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.inject.Inject; import javax.jcr.Node; import javax.jcr.NodeIterator; import javax.jcr.PathNotFoundException; import javax.jcr.RepositoryException; import javax.jcr.Session; import org.springframework.dao.DataIntegrityViolationException; import org.springframework.dao.DataRetrievalFailureException; import org.springframework.stereotype.Repository; import org.springframework.transaction.annotation.Transactional; import org.springmodules.jcr.JcrCallback; import org.springmodules.jcr.SessionFactory; import org.springmodules.jcr.support.JcrDaoSupport; import com.springinpractice.ch12.dao.ArticleDao; import com.springinpractice.ch12.model.Article; import com.springinpractice.ch12.model.Page; @Repository @Transactional(readOnly = true) public class JcrArticleDao extends JcrDaoSupport implements ArticleDao #1 @Inject private ArticleMapper articleMapper; #2 @Inject public void setSessionFactory(SessionFactory sessionFactory) #3 super.setSessionFactory(sessionFactory); @Transactional(readOnly = false) public void create(final Article article) #4 notNull(article); getTemplate().execute(new JcrCallback() #5 public Object doInJcr(Session session) throws IOException, RepositoryException if (exists(article.getId())) throw new DataIntegrityViolationException( “Article already exists”); #6 articleMapper.addArticleNode(article, getArticlesNode(session)); session.save(); return null; , true); ... various other DAO methods ... private String getArticlesNodeName() return “articles”; private String getArticlesPath() return “/” + getArticlesNodeName(); private String getArticlePath(String articleId) return getArticlesPath() + “/” + articleId;

private Node getArticlesNode(Session session) throws RepositoryException try return session.getNode(getArticlesPath()); catch (PathNotFoundException e) return session.getRootNode().addNode(getArticlesNodeName()); #1 Class definition #2 Map between articles and nodes #3 Creates JCR sessions #4 Writes method #5 Using JcrTemplate #6 Throws DataAccessException The JcrArticleDao class illustrates some ways in which we can use Spring to augment JCR. The first part is our high-level class definition (#1). We implement the ArticleDao interface from listing 3, and also extend JcrDaoSupport, which is part of Spring Modules JCR. JcrDaoSupport gives us access to JCR Sessions, a JcrTemplate, and a convertJcrAccessException(RepositoryException) method that converts JCR RepositoryExceptions to exceptions in the Spring DataAccessException hierarchy. We also declare the @Repository annotation to support component scanning and the @Transactional annotation to support transactions. Transactions on the DAO? It might surprise you that we’re annotating a DAO with @Transactional. After all, we usually define transactions on service beans since any given service method might make multiple DAO calls that need to happen within the scope of a single atomic transaction. However, we’re not going to have service beans—we’re going to wire our ArticleDao right into the controller itself. The reason is that our service methods would simply pass-through to ArticleDao and, in that sort of situation, there’s really no benefit to going through the ceremony of defining an explicit service layer. If we were to extend our simple app to something with real service methods (as opposed to data access methods), we’d build a transactional service layer. At #2, we inject an ArticleMapper, which is a custom class that converts back and forth between Articles and JCR Nodes. We’ll see that in listing 5 below. We override JcrDaoSupport.setSessionFactory() at (#3). We do this just to make the property injectable through the component scanning mechanism, since JcrDaoSupport doesn’t itself support that. Our create() method (#4) is one of our CRUD methods. We’ve suppressed the other ones since we’re more interested in covering Spring than the details of using JCR, but the code download has the other methods. We’ve annotated it with @Transactional(readOnly = false) to override the class-level @Transactional(readOnly = true) annotation. See the code download for the rest of the methods. We’ve chosen to implement our DAO methods using the template method pattern common throughout Spring (JpaTemplate, HibernateTemplate, JdbcTemplate, RestTemplate, and so on). In this case, we’re using the Spring Modules JCR JcrTemplate (via JcrDaoSupport.getTemplate()) and its corresponding JcrCallback interface (#5). This template is helpful because it automatically handles concerns such as opening and closing JCR sessions, managing the relationship between sessions and transactions, and translating RepositoryExceptions and IOExceptions into the Spring DataAccessException hierarchy. Finally, to maintain consistency with JcrDaoSupport’s exception translation mechanism, we throw a DataIntegrityViolationException (#6) (part of the aforementioned DataAccessException hierarchy) in the event of a duplicate article. We’ve mentioned Spring Modules JCR a few times here. Let’s talk about that briefly. A word about Spring Modules JCR Spring Modules is a now-defunct project that includes several useful Spring-style libraries for integrating with various not-quite-core APIs and codebases, including Ehcache, OScache, Lucene, and JCR (among several others). Unfortunately, some promising attempts to revive Spring Modules, either in whole or in part, appear to have stalled. It’s unclear whether Spring will ever directly support JCR, but there’s a lot of good Spring/JCR code in the Spring Modules project, and I wanted to use it for this writing.

To that end I (Willie) forked an existing Spring Modules JCR effort on GitHub to serve as a stable-ish basis for Spring in Practice’s code. I’ve made some minor enhancements (mostly around cleaning up the POM and elaborating support for namespace-based configuration) to make Spring/JCR integration easier. Note, however, that I don’t have any plans around building this fork out beyond our present needs. The reality is that integrating Spring and JCR currently requires a bit of extra effort because there isn’t an established project for doing that. In our discussion of the JcrArticleDao, we mentioned an ArticleMapper component to convert between articles and JCR nodes. The listing below presents the ArticleMapper. Listing 5 ArticleMapper.java converts between articles and JCR nodes package com.springinpractice.ch12.dao.jcr; import java.util.Calendar; import java.util.Date; import javax.jcr.Node; import javax.jcr.RepositoryException; import org.springframework.stereotype.Component; import com.springinpractice.ch12.model.Article; import com.springinpractice.ch12.model.Page; @Component public class ArticleMapper public Article toArticle(Node node) throws RepositoryException #1 Article article = new Article(); article.setId(node.getName()); article.setTitle(node.getProperty(“title”).getString()); article.setAuthor(node.getProperty(“author”).getString()); if (node.hasProperty(“publishDate”)) article.setPublishDate( node.getProperty(“publishDate”).getDate().getTime()); if (node.hasProperty(“description”)) article.setDescription(node.getProperty(“description”).getString()); if (node.hasProperty(“keywords”)) article.setKeywords(node.getProperty(“keywords”).getString()); return article; public Node addArticleNode(Article article, Node parent) #2 throws RepositoryException Node node = parent.addNode(article.getId()); node.setProperty(“title”, article.getTitle()); node.setProperty(“author”, article.getAuthor()); Date publishDate = article.getPublishDate(); if (publishDate != null) Calendar cal = Calendar.getInstance(); cal.setTime(publishDate); node.setProperty(“publishDate”, cal); String description = article.getDescription(); if (description != null) node.setProperty(“description”, description); String keywords = article.getKeywords(); if (keywords != null) node.setProperty(“keywords”, keywords); Node pagesNode = node.addNode(“pages”, “nt:folder”); int numPages = article.getPages().size(); for (int i = 0; i < numPages; i++) Page page = article.getPages().get(i); addPageNode(pagesNode, page, i + 1); return node; private void addPageNode(Node pagesNode, Page page, int pageNumber) #3 throws RepositoryException Node pageNode = pagesNode.addNode(String.valueOf(pageNumber), “nt:file”); Node contentNode = pageNode.addNode(Node.JCR_CONTENT, “nt:resource”); contentNode.setProperty(“jcr:data”, page.getContent()); #1 Maps Node to Article #2 Maps Article to Node #3 Maps Page to Node Listing 5 is more concerned with mapping code rather than Spring techniques, but we’re including it here to give you a sense for what coding against JCR looks like just in case you’re unfamiliar with it. We use toArticle() (#1) to map a JCR Node to an Article. Then we have addArticleNode() (#2) and addPageNode() (#3) to convert Articles and Pages to Nodes, respectively. In the listing below, we bring everything together with our Spring configuration. Listing 6 beans-jcr.xml, the Spring beans configuration for the JCR repo

xmlns:context=“http://www.springframework.org/schema/context” xmlns:jcr=“http://springmodules.dev.java.net/schema/jcr” #1 xmlns:jackrabbit=“http://springmodules.dev.java.net/schema/jcr/jackrabbit” #2 xmlns:p=“http://www.springframework.org/schema/p” xmlns:tx=“http://www.springframework.org/schema/tx” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=“ http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://springmodules.dev.java.net/schema/jcr http://springmodules.dev.java.net/schema/jcr/springmodules-jcr.xsd http://springmodules.dev.java.net/schema/jcr/jackrabbit http://springmodules.dev.java.net/schema/jcr/springmodules-jackrabbit.xsd”> #3 homeDir=“$repository.dir” configuration=“$repository.conf” /> #4 #5 repository=“repository” credentials=“credentials” /> #6 #7 #8 #9

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CouchDB 3.4.1 Released

https://blog.couchdb.org/2024/09/27/3-4-1/

[suncloudvn]

ACID Database là gì? Thuộc tính quan trọng trong cơ sở dữ liệu

Trong thế giới công nghệ thông tin hiện đại, khi các ứng dụng và hệ thống trở nên phức tạp hơn, nhu cầu về tính toàn vẹn dữ liệu và tính nhất quán trở nên quan trọng hơn bao giờ hết. Đây là nơi mà khái niệm ACID trở thành nền tảng, giúp đảm bảo rằng các giao dịch cơ sở dữ liệu được thực hiện một cách đáng tin cậy. Cùng tìm hiểu ACID Database là gì cũng như đặc điểm của nó trong bài viết dưới đây nhé.

1. ACID Database là gì?

ACID Database là một khái niệm quan trọng trong lĩnh vực quản trị cơ sở dữ liệu, đặc biệt là đối với các hệ quản trị cơ sở dữ liệu quan hệ (RDBMS). ACID là viết tắt của bốn thuộc tính chính: Atomicity (tính nguyên tử), Consistency (tính nhất quán), Isolation (tính cô lập) và Durability (tính bền vững). Các thuộc tính này đảm bảo rằng các giao dịch trong cơ sở dữ liệu được thực hiện một cách an toàn và tin cậy.

Tính nguyên tử (Atomicity)

Tính nguyên tử đảm bảo rằng một giao dịch cơ sở dữ liệu sẽ được thực hiện hoàn toàn hoặc không thực hiện chút nào. Điều này có nghĩa là mọi thay đổi trong cơ sở dữ liệu phải được hoàn tất thành công; nếu không, hệ thống sẽ khôi phục trạng thái ban đầu trước khi giao dịch bắt đầu. Tính nguyên tử bảo vệ dữ liệu khỏi những rủi ro khi hệ thống gặp sự cố giữa chừng trong quá trình thực hiện giao dịch.

Ví dụ, trong một giao dịch chuyển tiền giữa hai tài khoản ngân hàng, nếu một bước nào đó trong quá trình gặp lỗi, hệ thống sẽ hoàn tác tất cả các thay đổi để đảm bảo rằng không có khoản tiền nào bị mất hoặc nhân đôi.

Tính nhất quán (Consistency)

Tính nhất quán đảm bảo rằng một giao dịch sẽ đưa cơ sở dữ liệu từ một trạng thái hợp lệ này sang một trạng thái hợp lệ khác. Điều này có nghĩa là mọi ràng buộc toàn vẹn của cơ sở dữ liệu phải được duy trì. Tính nhất quán thường được kiểm soát bởi các quy tắc, ràng buộc và logic được xác định trước trong thiết kế cơ sở dữ liệu.

Một ví dụ về tính nhất quán là một cơ sở dữ liệu kiểm tra rằng không có hai người dùng nào có cùng một ID. Nếu một giao dịch cố gắng thêm một người dùng với ID đã tồn tại, giao dịch đó sẽ bị từ chối để duy trì tính nhất quán của dữ liệu.

Tính cô lập (Isolation)

Tính cô lập đảm bảo rằng các giao dịch đồng thời không can thiệp lẫn nhau. Mỗi giao dịch sẽ được thực hiện như thể nó là giao dịch duy nhất trên hệ thống. Các thay đổi thực hiện bởi một giao dịch sẽ không hiển thị với các giao dịch khác cho đến khi giao dịch đó hoàn tất.

Điều này rất quan trọng trong các hệ thống đa người dùng, nơi nhiều giao dịch có thể diễn ra đồng thời. Ví dụ, trong một cửa hàng trực tuyến, nhiều khách hàng có thể đặt hàng cùng một lúc. Tính cô lập đảm bảo rằng mỗi đơn hàng được xử lý một cách chính xác mà không bị ảnh hưởng bởi các giao dịch khác.

Tính bền vững (Durability)

Tính bền vững đảm bảo rằng một khi giao dịch đã hoàn tất, các thay đổi dữ liệu sẽ được lưu trữ vĩnh viễn, ngay cả khi hệ thống gặp sự cố sau đó. Điều này thường được thực hiện thông qua việc ghi lại các thay đổi vào nhật ký giao dịch hoặc sao lưu dữ liệu.

Ví dụ, sau khi một giao dịch ngân hàng hoàn tất, dữ liệu về giao dịch đó sẽ được ghi vào hệ thống sao lưu để đảm bảo rằng thông tin không bị mất đi trong trường hợp hệ thống gặp sự cố.

2. Ứng dụng hiện đại của ACID

Trong bối cảnh hiện đại, các hệ thống cơ sở dữ liệu cần xử lý lượng dữ liệu lớn và phức tạp hơn bao giờ hết. Các nguyên tắc ACID vẫn là nền tảng cho sự phát triển và vận hành của các hệ thống này, từ các cơ sở dữ liệu quan hệ truyền thống như MySQL và PostgreSQL, đến các cơ sở dữ liệu phân tán và NoSQL như MongoDB và Cassandra.

Cơ sở dữ liệu quan hệ

Trong các cơ sở dữ liệu quan hệ, ACID là tiêu chuẩn vàng. Các hệ thống như Oracle, SQL Server và PostgreSQL sử dụng các nguyên tắc này để đảm bảo tính toàn vẹn và độ tin cậy của dữ liệu. Các tính năng như khóa giao dịch, ràng buộc toàn vẹn và nhật ký giao dịch đều dựa trên nguyên tắc ACID.

Cơ sở dữ liệu NoSQL

Trong các cơ sở dữ liệu NoSQL, như MongoDB, Cassandra, và CouchDB, việc áp dụng các nguyên tắc ACID có thể khác biệt. NoSQL thường được thiết kế để xử lý lượng dữ liệu rất lớn và phân phối trên nhiều nút mạng. Một số hệ thống NoSQL cung cấp tính năng ACID đầy đủ cho các giao dịch đơn lẻ, trong khi các hệ thống khác có thể chỉ cung cấp tính nhất quán cuối cùng thay vì tính nhất quán tức thì.

Cơ sở dữ liệu phân tán

Với sự gia tăng của các ứng dụng đám mây và cơ sở dữ liệu phân tán, việc duy trì các thuộc tính ACID trở nên phức tạp hơn. Các hệ thống như Google Spanner và Amazon Aurora đã phát triển các công nghệ tiên tiến để cung cấp tính nhất quán mạnh mẽ và độ bền vững trong các môi trường phân tán.

3. Câu hỏi thường gặp

Tại sao ACID lại quan trọng trong cơ sở dữ liệu?

ACID đảm bảo tính toàn vẹn và độ tin cậy của dữ liệu. Nó giúp ngăn ngừa các vấn đề như mất dữ liệu, dữ liệu không nhất quán, và các lỗi có thể xảy ra khi các giao dịch được thực hiện đồng thời.

Làm thế nào để cơ sở dữ liệu đảm bảo tính ACID?

Các hệ quản trị cơ sở dữ liệu (DBMS) đảm bảo tính ACID thông qua các cơ chế như khóa (locks), giao dịch (transactions) và nhật ký giao dịch (transaction logs). Các cơ chế này giúp quản lý các giao dịch và bảo vệ dữ liệu khỏi các lỗi có thể xảy ra.

ACID có thể ảnh hưởng đến hiệu suất của cơ sở dữ liệu không?

Có, việc đảm bảo các thuộc tính ACID có thể làm giảm hiệu suất của cơ sở dữ liệu do các chi phí liên quan đến việc quản lý giao dịch, khóa và nhật ký giao dịch. Tuy nhiên, lợi ích của tính toàn vẹn và độ tin cậy của dữ liệu thường vượt trội hơn so với các chi phí này trong nhiều ứng dụng.

Kết Luận

ACID Database là một phần quan trọng của cơ sở dữ liệu hiện đại, đảm bảo dữ liệu được quản lý một cách nhất quán và tin cậy. Từ các cơ sở dữ liệu quan hệ truyền thống đến các hệ thống NoSQL và phân tán hiện đại, các nguyên tắc ACID giúp bảo vệ dữ liệu khỏi các lỗi và đảm bảo tính toàn vẹn của giao dịch. Trong một thế giới ngày càng phụ thuộc vào dữ liệu, việc hiểu và áp dụng các nguyên tắc ACID là điều không thể thiếu đối với các nhà phát triển và quản trị viên cơ sở dữ liệu.

 Nguồn: https://suncloud.vn/acid-database

[webouns01]

Technologies Used in Web Development

Web development is an ever-evolving field that involves a variety of technologies to create, design, and maintain websites. These technologies range from fundamental building blocks to advanced tools that enhance functionality and user experience. This article provides an overview of the key technologies used in web development.

1. HTML (HyperText Markup Language)

Overview

It defines the content and layout of a website, allowing browsers to display text, images, links, and other multimedia elements.

Key Features

Markup Structure:Utilizes tags to structure content.

Cross-Platform Compatibility:Works across different browsers and devices.

SEO Friendly:Helps in optimizing web pages for search engines.

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2. CSS (Cascading Style Sheets)

Overview

CSS is used to style and layout web pages. It allows developers to apply styles such as fonts, colors, spacing, and positioning to HTML elements, enhancing the visual presentation of web pages.

Key Features

Separation of Content and Design:Keeps HTML structure separate from design aspects.

Responsive Design:Facilitates the creation of mobile-friendly websites.

Reusability:Styles can be reused across multiple pages.

3. JavaScript

Overview

 It is essential for creating responsive user interfaces and enhancing user experience.

Key Features

Client-Side Scripting:Runs directly in the browser without server-side processing.

Event Handling:Responds to user actions like clicks, mouseovers, and key presses.

APIs and Libraries:Supports numerous libraries and frameworks, such as React and Angular.

4. Front-End Frameworks

Overview

Front-end frameworks simplify the development process by providing reusable components and standardized practices. Popular frameworks include:

Angular:A comprehensive framework developed by Google for building dynamic web applications.

Vue.js:A progressive framework for building user interfaces, known for its simplicity and flexibility.

Key Features

Component-Based Architecture:Encourages reusability and maintainability.

Enhanced Performance:Optimizes rendering and improves load times.

Community Support:Extensive documentation and community resources.

5. Back-End Technologies

Overview

Back-end technologies handle server-side operations, database interactions, and application logic. Key back-end technologies include:

PHP:A widely-used scripting language for server-side development, often paired with databases like MySQL.

Key Features

Server-Side Logic:Manages database operations, authentication, and business logic.

APIs:Facilitates communication between the server and client.

Scalability:Supports the development of scalable web applications.

6. Databases

Overview

Databases store and manage data for web applications. 

SQL Databases:Structured databases such as MySQL, PostgreSQL, and Microsoft SQL Server.

NoSQL Databases:Unstructured databases like MongoDB and CouchDB, known for their flexibility and scalability.

Key Features

Data Management:Efficiently handles data storage, retrieval, and manipulation.

Security:Ensures data integrity and security.

Scalability:Supports handling large volumes of data and high traffic.

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7. Version Control Systems

Overview

Version control systems (VCS) help developers manage and track changes to their code. The most popular VCS is Git, often used in conjunction with platforms like GitHub and GitLab.

Key Features

Collaboration:Facilitates team collaboration and code sharing.

History Tracking:Maintains a history of changes, allowing for easy rollbacks.

Branching and Merging:Supports parallel development and feature integration.

8. DevOps and Deployment Tools

Overview

DevOps practices and deployment tools automate and streamline the development, testing, and deployment processes. Common tools include:

Docker:Containers that encapsulate applications for consistency across environments.

Jenkins:An automation server for continuous integration and continuous delivery (CI/CD).

Kubernetes:Orchestrates containerized applications for scalability and reliability.

Key Features

Automation:Reduces manual intervention and errors.

Scalability:Ensures applications can scale to meet demand.

Monitoring and Maintenance:Provides tools for monitoring application performance and health.

[godigiinfotech1]

The Foundation of Web Applications - An Complete Guide to Back-End Development

Front-end developer focus on the user interface & Back-end developer manage the server-side logic & database management that drive web applications. We will look at important technologies, suggested methods for aspiring full stack engineers, and the basic concepts of back-end development in this blog.

Understanding of Back-End Development

Building and maintaining the server, database, and application logic are all part of back-end development. It guarantees that data is appropriately processed, accessed, and saved, offering the capability required for front-end users to interact with .

Key Back-End Technologies

Server-Side Languages:

Node.js :

Purpose -the purpose is JavaScript runtime built on Chrome’s V8 engine, used for building fast & scalable server-side applications.

Key Concepts - Event-driven architecture, non-blocking I/O, Express framework.

Best Practices - Use middleware effectively, manage errors, optimize performance.

Python :

Purpose - Advanced interpreted language that is famous for being fast and understandable.

Key Concepts - ORM (Object-Relational Mapping), RESTful APIs, and the Flask and Django frameworks.

Best Practices - Create clean code, implement virtual environments, and follow to PEP 8 principles.

Ruby:

Purpose - Dynamic, object-oriented language designed for simplicity and productivity.

Key Concepts - Ruby on Rails framework, MVC architecture, Active Record.

Best Practices: Use gems judiciously, follow the Ruby style guide, test extensively.

Databases :

SQL Databases:

Examples - MySQL, PostgreSQL.

Key Concepts - Structured query language, relational tables, ACID properties.

Best Practices - Normalize databases, use indexes, backup regularly.

NoSQL Databases:

Examples - MongoDB, CouchDB.

Key Concepts - Document stores, key-value pairs, schema flexibility.

Best Practices - Optimize for read/write performance, use appropriate data models, ensure data integrity.

Back-End Frameworks

Express.js (Node.js):

Purpose - Minimalist web framework for Node.js.

Key Concepts - Middleware, routing, request/response handling.

Best Practices - Modularize routes, use environment variables, handle errors gracefully.

Django (Python):

Purpose - High level web framework that promotes efficient development & clean, pragmatic design.

Key Concepts - ORM, URL routing, template engine.

Best Practices - Follow the Django project structure, use Django’s built-in admin, secure your application.

Ruby on Rails:

Purpose - Server-side web application framework written in Ruby.

Key Concepts - Convention over configuration, Active Record, RESTful design.

Best Practices - Adhere to Rails conventions, use strong parameters, implement caching.

APIs and RESTful Services

Purpose: API - Application Programming Interfaces allows different software systems to communicate. REST API is common approach to create APIs.

Key Concepts - HTTP methods (GET, POST, PUT, DELETE), endpoints, JSON data format.

Best Practices - Design intuitive endpoints, use proper HTTP status codes, document your API.

Authentication and Security

Authentication Methods:

Session Based - Storing user session data on the server.

Token Based - Using tokens (example JWT) to authenticate requests.

OAuth - Third-party authentication (example logging in with Google).

Security Best Practices:

Data Encryption - Use SSL/TLS for secure communication.

Access Control - Implement proper user roles and permissions.

For online applications to be secure, trustworthy & effective, back-end development is important. You can guarantee the smooth and secure operation of your apps by become an expert in server-side languages, databases, frameworks, and best practices. Maintaining proficiency in a continuously developing sector needs continuous learning and practice.

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[citynewsglobe]

[ad_1] As of late, the demand for NoSQL databases is on the rise. The rationale behind their immense recognition is that corporations want NoSQL databases to deal with a large quantity of buildings in addition to unstructured information. This isn't potential to attain with conventional relational or SQL databases. With elevated digitization, trendy companies must take care of large information commonly, coping with hundreds of thousands of customers whereas ensuring that there aren't any interruptions in delivering the information administration providers. All these expectations are the explanations behind the recognition of NoSQL databases in nearly each business. There may be all kinds of NoSQL databases accessible, companies usually get confused with NoSQL vs SQL and search instruments which might be extra succesful, agile, and versatile to handle big huge information. This weblog specifies the highest 7 NoSQL databases that companies can choose as per their distinctive wants. All these NoSQL databases are open supply and encompass free variations. All the restrictions of conventional relational databases comparable to efficiency, velocity, scalability, and even huge information administration may be dealt with with these NoSQL databases. Nevertheless, it's crucial to think about that these databases are used to fulfill solely superior necessities of the organizations as frequent purposes can nonetheless be constructed by conventional SQL databases. So, let’s try the highest 7 NoSQL databases that may even change into widespread in 2024. Apache Cassandra: Apache Cassandra is an open-source, free, and high-performance database. That is also called scalable and fault tolerant for each cloud infrastructure and commodity hardware. It might simply handle failed node replacements and replicate the information for a number of nodes mechanically. On this NoSQL database, you too can have the choice to decide on both synchronous replication or asynchronous replication. Apache HBase: Apache HBase can also be the perfect NoSQL database, which is Referred to as an open-source distributed Hadoop database. That is utilized to put in writing and skim the massive information. It has been developed to handle even the billions of rows and columns by way of the commodity hardware cluster. The options of Apache HBase embody computerized sharding of tables, scalability, constant writing & studying capabilities, and even nice assist for server failure. Apache CouchDB: Apache CouchDB can also be an open supply in addition to a single node database that helps in storing and managing the information. It might additionally scale up complicated initiatives right into a cluster of nodes on a number of servers. Firms can anticipate its integration with HTTP proxy servers together with the assist of HTTP protocol and JSON information format. This database is designed with crash-resistant options and reliability that saves information redundancy, which implies companies by no means lose their information and entry it each time wanted. MarkLogic Server:   The MarkLogic server is the main NoSQL doc database that's designed for managing giant volumes of unstructured information and complicated information buildings. It boasts an amazing mixture of options for information-intensive apps and complicated content material administration necessities. It's broadly used for storing in addition to managing XML info. Companies can outline schemas of their information utilizing the MarkLogic server whereas accommodating variations within the doc construction. Furthermore, it provides extra flexibility as in comparison with relational SQL databases. Amazon DynamoDB: Amazon DynamoDB is the important thing worth, serverless, and doc database, which is obtainable by AWS (Amazon Net providers. This database is designed for increased scalability and efficiency.  It's in excessive demand amongst companies to construct trendy purposes that want ultra-fast accessi

bility of knowledge in addition to the potential to deal with large information and consumer visitors, DynamoDB additionally gives restricted assist for ACID, the place ACID implies as Atomicity, Consistency, Isolation, and Sturdiness. IBM Cloudant: IBM Cloudant is one other widespread NoSQL database that's provided by IBM within the type of a cloud-based service. It's a full-featured and versatile  JSON doc database used for cell, net, and serverless purposes that want better flexibility, scalability, and efficiency. This NoSQL database can also be developed for horizontal scaling. it's simpler so as to add extra servers on this database to handle unprecedented ranges of knowledge and consumer visitors. MongoDB: MongoDB is the greatest NoSQL database accessible available in the market. Like many different NoSQL databases, it shops and manages information in JSON-like paperwork. The versatile schema method helps companies leverage the evolving information fashions with none want for typical desk buildings. It may also be scaled horizontally by including extra shards to the cluster. Companies can simply deal with large quantities of knowledge and visitors with MongoDB. The Remaining Thought Utilizing NoSQL databases that match completely to your wants ends in effectivity beneficial properties. It makes it simpler for companies to retailer, course of, and handle large quantities of unstructured information effectively. The put up  Prime 7 NoSQL Databases You Can Use in 2024 appeared first on Vamonde. [ad_2] Supply hyperlink

[triple--a--threat]

fly.io cmon you know its me. let me deploy my couchdb server damn 😭

[edchart]

CouchDB Certification Exam Free Test - By EDCHART free Online

CouchDB is a document-oriented NoSQL database that stores data in JSON-like documents with a flexible schema. It provides a distributed architecture, allowing seamless scalability and fault tolerance. CouchDB's key features include multi-version concurrency control (MVCC), HTTP/RESTful API, and a MapReduce engine for querying data.

[kennak]

完全なクエリ システムをフロントエンドに移動することは、ほとんどのフロントエンド開発者が本当に望んでいることだと思います。 彼らは、トランスポート層、REST、GraphQL、*RPC などを継続的に再発明するのではなく、データに対するフルパワーのクエリ システムを望んでいます。 専門のバックエンド チームとフロントエンド チームがいるほとんどの従来のウェブ ショップでこのようなシステムを採用するのは困難です。 データベース、バックエンド、トランスポート、認証レイヤーを取り出して、この単一のブロック システムに置き換えます。 ほとんどのシステム アーキテクトはバックエンドで育ったので、一般にこの問題についてはほとんど無知です。 双方に広範囲に影響するため、おそらくこれを既存のシステムに適合させることはできず、未開拓の新規開発のみが残されます。 最後に、バックエンドは AWS または Asure サービスではなく、ラムダフレンドリーでもありません。 これらすべては、私が話をするほとんどの建築家タイプが決してそれに触れないことを意味します。 このスタイルのシステムのほとんどは、CouchDB+PouchDB という古い技術ですでに存在しています。 これはいくつかの点では非常にうまく機能します。 欠点は、クエリ システムが実際には理想的ではなく、認証とデータ スコープ システムがほとんどの人にとって非常に馴染みのないことです。 最も扱いやすいモデルは、データが 1 人のユーザーによって完全に所有されている場合で、すぐに使用できるユーザーごとのデータベース モデルを使用します。 CRDT による高度なデータ セグメンテーションにより、多くの競合の問題が解消されます。 ただし、スケーリングの問題があり、10,000 から 100,000 のユーザーを接続する場合、CouchDB には非常に高い CPU 要件が必要になります。 技術は維持されていますが歯に長いです。 システム設計の面では、ユーザー間でデータを共有し始めると非常に複雑になりますが、複雑さを解決するのではなく単に移動するだけなので、むしろ不向きです。 このアプローチは同じ目標を達成しているように見えますが、同様のスケーリングの問題が発生する可能性があります。 システムの進化にご期待ください。 世界への第一歩のようです。

誤ってデータベースをプログラミングしてしまう | ハッカーニュース