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50-563: Ruby on Rails (simplified as Rails ) is a server-side web application framework written in Ruby under the MIT License . Rails is a model–view–controller (MVC) framework, providing default structures for a database , a web service , and web pages . It encourages and facilitates the use of web standards such as JSON or XML for data transfer and HTML , CSS and JavaScript for user interfacing. In addition to MVC, Rails emphasizes

100-455: A model in the Ruby on Rails framework maps to a table in a database and to a Ruby file. For example, a model class User will usually be defined in the file 'user.rb' in the app/models directory, and linked to the table 'users' in the database. While developers are free to ignore this convention and choose differing names for their models, files, and database table, this is not common practice and

150-523: A PERSON. Important points to note:- The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table. In database relational modeling and implementation, a candidate key is a set of zero or more attributes, the values of which are guaranteed to be unique for each tuple (row) in a relation. The value or combination of values of candidate key attributes for any tuple cannot be duplicated for any other tuple in that relation. Since

200-457: A basic website . Also included are WEBrick , a simple Ruby web server that is distributed with Ruby, and Rake , a build system, distributed as a gem . Together with Ruby on Rails, these tools provide a basic development environment. Ruby on Rails is most commonly not connected to the Internet directly, but through some front-end web server . Mongrel was generally preferred over WEBrick in

250-403: A controller implementing a flight-search function would need to query a model representing individual flights to find flights matching the search, and might also need to query models representing airports and airlines to find related secondary data. The controller might then pass some subset of the flight data to the corresponding view, which would contain a mixture of static HTML and logic that use

300-439: A default online rich-text editor , parallel testing, multiple database support, mailer routing and a new autoloader. Rails 6.1 was released on 9 December 2020, adding per-database connection switching, horizontal database sharding , eager loading of all associations, Delegated Types as an alternative to single-table inheritance, asynchronous deletion of associations, error objects, and other improvements and bug fixes. Rails 7.0

350-488: A foreign key when a change is needed. Foreign keys play an essential role in database design . One important part of database design is making sure that relationships between real-world entities are reflected in the database by references, using foreign keys to refer from one table to another. Another important part of database design is database normalization , in which tables are broken apart and foreign keys make it possible for them to be reconstructed. Multiple rows in

400-512: A particular supplier. Supplier details (such as name and address) are kept in a separate table; each supplier is given a 'supplier number' to identify it. Each invoice record has an attribute containing the supplier number for that invoice. Then, the 'supplier number' is the primary key in the Supplier table. The foreign key in the Invoice table points to that primary key. The relational schema is

450-453: A polite protest in the Ruby on Rails community. In response to this criticism, Hansson replied: I only grant promotional use [of the Rails logo] for products I'm directly involved with. Such as books that I've been part of the development process for or conferences where I have a say in the execution. I would most definitely seek to enforce all the trademarks of Rails. The trademark of the logo

500-416: A row may not be able to fully cascade because the row is referenced by data your transaction cannot "see", and therefore cannot cascade onto. An example: while your transaction is attempting to renumber a customer account, a simultaneous transaction is attempting to create a new invoice for that same customer; while a CASCADE rule may fix all the invoice rows your transaction can see to keep them consistent with

550-486: A row of the referenced table. For example, consider a database with two tables: a CUSTOMER table that includes all customer data and an ORDER table that includes all customer orders. Suppose the business requires that each order must refer to a single customer. To reflect this in the database, a foreign key column is added to the ORDER table (e.g., CUSTOMERID), which references the primary key of CUSTOMER (e.g. ID). Because

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600-436: A self-referencing or recursive foreign key. In database management systems, this is often accomplished by linking a first and second reference to the same table. A table may have multiple foreign keys, and each foreign key can have a different parent table. Each foreign key is enforced independently by the database system . Therefore, cascading relationships between tables can be established using foreign keys. A foreign key

650-505: A set of attributes that references a candidate key. For example, a table called TEAM may have an attribute, MEMBER_NAME, which is a foreign key referencing a candidate key, PERSON_NAME, in the PERSON table. Since MEMBER_NAME is a foreign key, any value existing as the name of a member in TEAM must also exist as a person's name in the PERSON table; in other words, every member of a TEAM is also

700-468: Is a reference to it from a referencing or child table. To understand RESTRICT (and CASCADE) better, it may be helpful to notice the following difference, which might not be immediately clear. The referential action CASCADE modifies the "behavior" of the (child) table itself where the word CASCADE is used. For example, ON DELETE CASCADE effectively says "When the referenced row is deleted from the other table (master table), then delete also from me ". However,

750-513: Is defined as an attribute or set of attributes in a relation whose values match a primary key in another relation. The syntax to add such a constraint to an existing table is defined in SQL:2003 as shown below. Omitting the column list in the REFERENCES clause implies that the foreign key shall reference the primary key of the referenced table. Likewise, foreign keys can be defined as part of

800-456: Is intended to emphasize Convention over Configuration (CoC), and the Don't Repeat Yourself (DRY) principle. The Rails Doctrine is an enduring enabler that guides the philosophy, design, and implementation of the Ruby on Rails framework. "Convention over Configuration" means a developer only needs to specify unconventional aspects of the application. For example, if there is a class Sale in

850-461: Is not supported by Microsoft SQL 2012 and earlier. NO ACTION and RESTRICT are very much alike. The main difference between NO ACTION and RESTRICT is that with NO ACTION the referential integrity check is done after trying to alter the table. RESTRICT does the check before trying to execute the UPDATE or DELETE statement. Both referential actions act the same if the referential integrity check fails:

900-498: Is often installed using RubyGems , a package manager which is included with current versions of Ruby. Many free Unix-like systems also support installation of Ruby on Rails and its dependencies through their native package management system . Ruby on Rails is typically deployed with a database server such as MySQL or PostgreSQL , and a web server such as Apache running the Phusion Passenger module. Ruby on Rails

950-502: Is the facility for RESTful web services. Rails 3.1 introduced Sass as standard CSS templating. By default, the server uses Embedded Ruby in the HTML views, with files having an html.erb extension. Rails supports swapping-in alternative templating languages, such as HAML and Mustache . Ruby on Rails 3.0 has been designed to work with Ruby 1.8.7, Ruby 1.9.2, and JRuby 1.5.2+; earlier versions are not supported. Ruby on Rails 3.2

1000-663: Is the last series of releases that support Ruby 1.8.7. Ruby on Rails is separated into various packages, namely ActiveRecord (an object-relational mapping system for database access), Action Pack, Active Support and Action Mailer. Prior to version 2.0, Ruby on Rails also included the Action Web Service package that is now replaced by Active Resource. Apart from standard packages, developers can make plugins to extend existing packages. Earlier Rails supported plugins within their own custom framework; version 3.2 deprecates these in favor of standard Ruby "gems". Ruby on Rails

1050-412: Is usually discouraged in accordance with the " convention-over-configuration " philosophy. A controller is a server-side component of Rails that responds to external requests from the web server to the application, by determining which view file to render. The controller may also have to query one or more models for information and pass these on to the view. For example, in an airline reservation system,

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1100-653: The CREATE TABLE SQL statement. If the foreign key is a single column only, the column can be marked as such using the following syntax: Foreign keys can be defined with a stored procedure statement. Because the database management system enforces referential constraints, it must ensure data integrity if rows in a referenced table are to be deleted (or updated). If dependent rows in referencing tables still exist, those references have to be considered. SQL:2003 specifies 5 different referential actions that shall take place in such occurrences: Whenever rows in

1150-541: The ActiveRecord module of Rails, the developer does not need to specify database column names in class definitions. Instead, Ruby on Rails can retrieve this information from the database based on the class name. "Fat models, skinny controllers" means that most of the application logic should be placed within the model while leaving the controller as light as possible. HTML Over The Wire (Hotwire), Conceptual compression, and robust security mark Rails 7.0's approach to

1200-591: The JavaScript libraries Prototype and Script.aculo.us for scripting Ajax actions. Ruby on Rails 3.0 separates the markup of the page (which defines the structure of the page) from scripting (which determines functionality or logic of the page). As of version 7.0, new Ruby on Rails applications come with the Hotwire family of JavaScript libraries installed by default. Since version 2.0, Ruby on Rails offers both HTML and XML as standard output formats. The latter

1250-487: The triggers or the semantics of the statement itself may yield an end state in which no foreign key relationships are violated by the time the constraint is finally checked, thus allowing the statement to complete successfully. In general, the action taken by the DBMS for SET NULL or SET DEFAULT is the same for both ON DELETE or ON UPDATE: the value of the affected referencing attributes is changed to NULL for SET NULL, and to

1300-568: The One person framework. In March 2007, David Heinemeier Hansson applied to register three Ruby on Rails-related trademarks with the USPTO . These applications concern the phrase "RUBY ON RAILS", the word "RAILS", and the official Rails logo. In the summer of 2007, Hansson denied the publisher Apress permission to use the Ruby on Rails logo on the cover of a new Ruby on Rails book written by some authoritative community members. The episode gave rise to

1350-527: The UPDATE or DELETE statement will result in an error. In other words, when an UPDATE or DELETE statement is executed on the referenced table using the referential action NO ACTION, the DBMS verifies at the end of the statement execution that none of the referential relationships are violated. This is different from RESTRICT, which assumes at the outset that the operation will violate the constraint. Using NO ACTION,

1400-401: The early days, but it can also run on Lighttpd , Apache , Cherokee , Hiawatha , Nginx (either as a module – Phusion Passenger for example – or via CGI , FastCGI or mod ruby ), and many others. From 2008 onward, Passenger replaced Mongrel as the most-used web server for Ruby on Rails. Ruby is also supported natively on IBM i . Ruby on Rails is also noteworthy for its extensive use of

1450-615: The flight data to create an HTML document containing a table with one row per flight. A controller may provide one or more actions. In Ruby on Rails, an action is typically a basic unit that describes how to respond to a specific external web-browser request. Also, note that the controller/action will be accessible for external web requests only if a corresponding route is mapped to it. Rails encourages developers to use RESTful routes, which include actions such as create, new, edit, update, destroy, show, and index. These mappings of incoming requests/routes to controller actions can be easily set up in

1500-539: The form_tag/form_for helpers. Rails 5.2 was released on 9 April 2018, introducing new features that include ActiveStorage, built-in Redis Cache Store, updated Rails Credentials and a new DSL that allows for configuring a Content Security Policy for an application. Rails 5.2.2 was released on 4 December 2018, introducing numerous bug fixes and several logic improvements. Rails 6.0 was released on 16 August 2019, making Webpack default, adding mailbox routing,

1550-421: 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 "products sold", that the developer needs to write code regarding these names. Generally, Ruby on Rails conventions lead to less code and less repetition. "Don't repeat yourself" means that information is located in a single, unambiguous place. For example, using

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1600-420: The parent (referenced) table are deleted (or updated), the respective rows of the child (referencing) table with a matching foreign key column will be deleted (or updated) as well. This is called a cascade delete (or update). A value cannot be updated or deleted when a row exists in a referencing or child table that references the value in the referenced table. Similarly, a row cannot be deleted as long as there

1650-730: The primary key of a table must be unique, and because CUSTOMERID only contains values from that primary key field, we may assume that, when it has a value, CUSTOMERID will identify the particular customer which placed the order. However, this can no longer be assumed if the ORDER table is not kept up to date when rows of the CUSTOMER table are deleted or the ID column altered, and working with these tables may become more difficult. Many real world databases work around this problem by 'inactivating' rather than physically deleting master table foreign keys, or by complex update programs that modify all references to

1700-514: The project management tool Basecamp at the web application company 37signals . Hansson first released Rails as open source in July 2004, but did not share commit rights to the project until February 2005. In August 2006, the framework reached a milestone when Apple announced that it would ship Ruby on Rails with Mac OS X v10.5 "Leopard" , which was released in October 2007. Rails version 2.3

1750-566: The purpose of the foreign key is to identify a particular row of referenced table, it is generally required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value. ). This rule is called a referential integrity constraint between the two tables. Because violations of these constraints can be the source of many database problems, most database management systems provide mechanisms to ensure that every non-null foreign key corresponds to

1800-417: The referencing (or child) table may refer to the same row in the referenced (or parent) table. In this case, the relationship between the two tables is called a one to many relationship between the referencing table and the referenced table. In addition, the child and parent table may, in fact, be the same table, i.e. the foreign key refers back to the same table. Such a foreign key is known in SQL:2003 as

1850-431: The referential action RESTRICT modifies the "behavior" of the master table, not the child table, although the word RESTRICT appears in the child table and not in the master table! So, ON DELETE RESTRICT effectively says: "When someone tries to delete the row from the other table (master table), prevent deletion from that other table (and of course, also don't delete from me, but that's not the main point here)." RESTRICT

1900-403: The renumbered customer row, it won't reach into another transaction to fix the data there; because the database cannot guarantee consistent data when the two transactions commit, one of them will be forced to roll back (often on a first-come-first-served basis.) As a first example to illustrate foreign keys, suppose an accounts database has a table with invoices and each invoice is associated with

1950-410: The routes.rb configuration file. A view in the default configuration of Rails is an erb file, which is evaluated and converted to HTML at run-time. Alternatively, many other templating systems can be used for views. Ruby on Rails includes tools that make common development tasks easier "out-of-the-box", such as scaffolding that can automatically construct some of the models and views needed for

2000-610: The specified default value for SET DEFAULT. Referential actions are generally implemented as implied triggers (i.e. triggers with system-generated names, often hidden.) As such, they are subject to the same limitations as user-defined triggers, and their order of execution relative to other triggers may need to be considered; in some cases it may become necessary to replace the referential action with its equivalent user-defined trigger to ensure proper execution order, or to work around mutating-table limitations. Another important limitation appears with transaction isolation : your changes to

2050-502: The stack. Rails 3.2 was released on 20 January 2012 with a faster development mode and routing engine (also known as Journey engine), Automatic Query Explain and Tagged Logging. Rails 3.2.x is the last version that supports Ruby 1.8.7. Rails 3.2.12 supports Ruby 2.0. Rails 4.0 was released on 25 June 2013, introducing Russian Doll Caching, Turbolinks , Live Streaming as well as making Active Resource, Active Record Observer and other components optional by splitting them as gems. Rails 4.1

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2100-1289: The use of other well-known software engineering patterns and paradigms, including convention over configuration (CoC), don't repeat yourself (DRY), and the active record pattern . Ruby on Rails' emergence in 2005 greatly influenced web app development, through innovative features such as seamless database table creations, migrations , and scaffolding of views to enable rapid application development. Ruby on Rails' influence on other web frameworks remains apparent today, with many frameworks in other languages borrowing its ideas, including Django in Python ; Catalyst in Perl ; Laravel , CakePHP and Yii in PHP ; Grails in Groovy ; Phoenix in Elixir ; Play in Scala ; and Sails.js in Node.js . Well-known sites that use Ruby on Rails include Airbnb , Crunchbase , Dribbble , GitHub , Twitch and Shopify . David Heinemeier Hansson extracted Ruby on Rails from his work on

2150-487: Was cancelled on 25 October 2019. Server-side Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.226 via cp1108 cp1108, Varnish XID 256931053 Upstream caches: cp1108 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 11:04:27 GMT Foreign key In other words, a foreign key is

2200-411: Was instituted in October 2024. Ruby on Rails evolves radically from release to release exploring the use of new technologies and adopting new standards on the Internet. Some features are very stable in Ruby on Rails while some are replaced in favour of new techniques. The model–view–controller (MVC) pattern is the fundamental structure to organize application programming. In a default configuration,

2250-505: 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. Merb was merged with Rails as part of the Rails 3.0 release. Rails 3.1 was released on 31 August 2011, featuring Reversible Database Migrations, Asset Pipeline, Streaming, jQuery as default JavaScript library and newly introduced CoffeeScript and Sass into

2300-491: Was released on 15 December 2021, replacing Node.js and Webpack with import maps for JavaScript management by default, replacing Turbolinks with a combination of Turbo and Stimulus, adding at-work encryption into Active Record, using Zeitwerk exclusively for code loading, and more. Rails 7.1 was released on 5 October 2023, Dockerfiles support using Kamal in order to deploy your application, authentication improvements, and now including support for bun . Ruby on Rails 8.0.0

2350-513: Was released on 15 March 2009, with major new developments in templates, engines, Rack and nested model forms. Templates enable the developer to generate a skeleton application with custom gems and configurations. Engines give developers the ability to reuse application pieces complete with routes, view paths and models. The Rack web server interface and Metal allow one to write optimized pieces of code that route around Action Controller. On 23 December 2008, Merb , another web application framework,

2400-415: Was released on 27 April 2017, introducing JavaScript integration changes (management of JavaScript dependencies from NPM via Yarn, optional compilation of JavaScript using Webpack , and a rewrite of Rails UJS to use vanilla JavaScript instead of depending on jQuery), system tests using Capybara , encrypted secrets, parameterized mailers, direct & resolved routes, and a unified form_with helper replacing

2450-485: Was released on 8 April 2014, introducing Spring, Variants, Enums, Mailer previews, and secrets.yml. Rails 4.2 was released on 19 December 2014, introducing Active Job, asynchronous emails, Adequate Record, Web Console, and foreign keys . Rails 5.0 was released on 30 June 2016, introducing Action Cable, API mode, and Turbolinks 5. Rails 5.0.0.1 was released on 10 August 2016, with Exclusive use of rails CLI over Rake and support for Ruby version 2.2.2 and above. Rails 5.1

2500-401: Was released on 8 November 2024. This major release introduces fundamental shifts in Rails development, enabling individual developers to host and manage their applications independently without the need for a Platform-as-a-service . The update focuses on empowering single developers to handle all aspects of application deployment and management seamlessly. A revised maintenance policy

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