You ain't gonna need it "You aren't gonna need it"[1][2] (acronym: YAGNI)[3] is a principle of extreme programming (XP) that states a programmer should not add functionality until deemed necessary.[4] Ron Jeffries writes, "Always implement things when you actually need them, never when you just foresee that you need them."[5] The phrase also appears altered as, "You aren't going to need it"[6][7] or sometimes phrased as, "You ain't gonna need it". YAGNI is a principle behind the XP practice of "do the simplest thing that could possibly work" (DTSTTCPW).[2][3] It is meant to be used in combination with several other practices, such as continuous refactoring, continuous automated unit testing and continuous integration. YAGNI is not universally accepted as a valid principle, even in combination with the supporting practices. Rationale[edit] See also[edit] References[edit] Jump up ^ Extreme Programming Installed, Ronald E.
Model–view–controller Model–view–controller (MVC) is a software pattern for implementing user interfaces. It divides a given software application into three interconnected parts, so as to separate internal representations of information from the ways that information is presented to or accepted from the user.[1][2] The central component, the model, consists of application data, business rules, logic and functions. A view can be any output representation of information, such as a chart or a diagram. Component interactions[edit] A typical collaboration of the MVC components In addition to dividing the application into three kinds of components, the Model–view–controller (MVC) design defines the interactions between them.[4] Use in web applications[edit] Although originally developed for desktop computing, model-view-controller has been widely adopted as an architecture for World Wide Web applications in all major programming languages. History[edit] See also[edit] References[edit] External links[edit]
KISS principle From Wikipedia, the free encyclopedia Design principle preferring simplicity A simple sign of the KISS principle (without the fourth word). Origin[edit] While popular usage has transcribed it for decades as "Keep it simple, stupid", Johnson transcribed it simply as "Keep it simple stupid" (no comma), and this reading is still used by many authors.[9] The principle is best exemplified by the story of Johnson handing a team of design engineers a handful of tools, with the challenge that the jet aircraft they were designing must be repairable by an average mechanic in the field under combat conditions with only these tools. The acronym has been used by many in the U.S. military, especially the U.S. Variants[edit] The principle most likely finds its origins in similar minimalist concepts, such as: Heath Robinson contraptions and Rube Goldberg's machines, intentionally overly-complex solutions to simple tasks or problems, are humorous examples of "non-KISS" solutions. Usage[edit] In politics[edit]
Convention over configuration Convention over configuration (also known as coding by convention) is a software design paradigm which seeks to decrease the number of decisions that developers need to make, gaining simplicity, but not necessarily losing flexibility. The phrase essentially means a developer only needs to specify unconventional aspects of the application. For example, if there's a class Sale in the model, the corresponding table in the database is called “sales” by default. It is only if one deviates from this convention, such as calling the table “sale”, that one needs to write code regarding these names. When the convention implemented by the tool matches the desired behavior, it behaves as expected without having to write configuration files. Only when the desired behavior deviates from the implemented convention is explicit configuration required. Motivation[edit] Some frameworks need multiple configuration files, each with many settings. Usage[edit] See also[edit] References[edit] External links[edit]
SOLID (object-oriented design) In computer programming, SOLID (Single responsibility, Open-closed, Liskov substitution, Interface segregation and Dependency inversion) is a mnemonic acronym introduced by Michael Feathers for the "first five principles" named by Robert C. Martin[1][2] in the early 2000s[3] that stands for five basic principles of object-oriented programming and design. The principles when applied together intend to make it more likely that a programmer will create a system that is easy to maintain and extend over time.[3] The principles of SOLID are guidelines that can be applied while working on software to remove code smells by causing the programmer to refactor the software's source code until it is both legible and extensible.
Active record pattern This pattern is commonly used by object persistence tools, and in object-relational mapping (ORM). Typically, foreign key relationships will be exposed as an object instance of the appropriate type via a property. Implementations[edit] Implementations of the concept can be found in various frameworks for many programming environments. For example, if in a database there is a table parts with columns name (string type) and price (number type), and the Active Record pattern is implemented in the class Part, the pseudo-code part = new Part() part.name = "Sample part" part.price = 123.45 part.save() will create a new row in the parts table with the given values, and is roughly equivalent to the SQL command INSERT INTO parts (name, price) VALUES ('Sample part', 123.45); Conversely, the class can be used to query the database: b = Part.find_first("name", "gearbox") This will find a new Part object based on the first matching row from the parts table whose name column has the value "gearbox".
GRASP (object-oriented design) General Responsibility Assignment Software Patterns (or Principles), abbreviated GRASP, consists of guidelines for assigning responsibility to classes and objects in object-oriented design. Larman states that "the critical design tool for software development is a mind well educated in design principles. It is not the UML or any other technology." Thus, GRASP is really a mental toolset, a learning aid to help in the design of object-oriented software. The Controller pattern assigns the responsibility of dealing with system events to a non-UI class that represents the overall system or a use case scenario. A Controller object is a non-user interface object responsible for receiving or handling a system event. A use case controller should be used to deal with all system events of a use case, and may be used for more than one use case (for instance, for use cases Create User and Delete User, one can have a single UserController, instead of two separate use case controllers).
rails/rails Separation of concerns The value of separation of concerns is simplifying development and maintenance of computer programs. When concerns are well-separated, individual sections can be reused, as well as developed and updated independently. Of special value is the ability to later improve or modify one section of code without having to know the details of other sections, and without having to make corresponding changes to those sections. Implementation[edit] Separation of concerns is an important design principle in many other areas as well, such as urban planning, architecture and information design.[5] The goal is to more effectively understand, design, and manage complex interdependent systems, so that functions can be reused, optimized independently of other functions, and insulated from the potential failure of other functions. Origin[edit] The term separation of concerns was probably coined by Edsger W. Let me try to explain to you, what to my taste is characteristic for all intelligent thinking.
Solution stack In computing, a solution stack is a set of software subsystems or components needed to perform a task without further external dependencies. For example, to develop a web application, the designer needs to use an operating system, web server, database, and programming language. Another version of a solution stack is operating system, middleware, database, and applications.[1] Linux-based solution stacks[edit] Linux (the operating system) Apache (the web server) MySQL or MariaDB (the database management systems) Linux (operating system) Apache (web server) Seaside (web framework) Smalltalk (programming language) The cloud stack of LEAP for: AppScale (Cloud computing-framework and free and open-source alternative to Google App Engine), OpenStack Linux – OpenStack controller nodes run exclusively on Linux OpenStack – providing an infrastructure as a service (IaaS) Ganeti Xen or KVM (hypervisor) Distributed Replicated Block Device (storage replication) Ganeti (virtual machine cluster management tool) Node.js
Is there a built-in login template in django Ruby on Rails Ruby on Rails emphasizes the use of well-known software engineering patterns and principles, such as active record pattern, convention over configuration (CoC), don't repeat yourself (DRY), and model–view–controller (MVC). History[edit] On December 23, 2008, Merb, another web application framework, was launched, and Ruby on Rails announced it would work with the Merb project to bring "the best ideas of Merb" into Rails 3, ending the "unnecessary duplication" across both communities.[7] Merb was merged with Rails as part of the Rails 3.0 release.[8][9] Rails 3.2 was released on January 20, 2012 with a faster development mode and routing engine (also known as Journey engine), Automatic Query Explain and Tagged Logging.[11] Rails 3.2.x is the last version that supports Ruby 1.8.7.[12] Rails 3.2.12 supports Ruby 2.0[13] Technical overview[edit] Like many web frameworks, Ruby on Rails uses the model–view–controller (MVC) pattern to organize application programming. Framework structure[edit]
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