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{{short description|Code generation technique or a project generation technique}}
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'''Scaffolding''', as used in computing, refers to one of two techniques: 
*'''Code generation''':
It is a technique related to database access in some [[model–view–controller]] [[software framework|framework]]s.
*'''Project generation''':
It is a technique supported by various programming tools.

==Code generation==
Scaffolding is a technique supported by some [[model–view–controller]] [[software framework|framework]]s, in which the programmer can specify how the application database may be used. The [[compiler]] or framework uses this specification, together with pre-defined code templates, to generate the final code that the application can use to [[create, read, update and delete]] database entries, effectively treating the templates as a "[[scaffolding|scaffold]]" on which to build a more powerful application.

Scaffolding is an evolution of database code generators from earlier development environments, such as Oracle's CASE Generator, and many other [[fourth-generation programming language|4GL]] client-server software development products.

Scaffolding was made popular by the [[Ruby on Rails]] framework. It has been adapted to other software frameworks, including [[OutSystems|OutSystems Platform]], [[Express.js|Express Framework]], Blitz.js, [[Play framework]], [[Django (web framework)|Django]], [[web2py]], [[MonoRail (software)|MonoRail]], Brail, [[Symfony]], [[Laravel]], [[CodeIgniter]], [[Yii]], [[CakePHP]], [[Phalcon (framework)|Phalcon PHP]], Model-Glue, [[PRADO (framework)|PRADO]], [[Grails (framework)|Grails]], [[Catalyst (software)|Catalyst]], [[Mojolicious]], [[JBoss Seam|Seam Framework]], [[Spring Roo]], [[JHipster]], [[ASP.NET Dynamic Data]], KumbiaPHP and [[ASP.NET MVC]] framework's Metadata Template Helpers.

===Run-time vs. design-time scaffolding===
Scaffolding can occur at two different phases of the [[Program lifecycle phase|program lifecycle]]: [[design time]] and [[Run time (program lifecycle phase)|run time]]. Design time scaffolding produces files of code that can later be modified by the programmer to customize the way the application database is used. However, for [[Programming in the large|large-scale applications]] this approach may be difficult to maintain due to the sheer number of files produced, and the fact that the design of the files was largely fixed when they were [[Copy and paste programming|generated or copied]] from the original templates.  Alternatively, run time scaffolding produces code on the fly.  It allows changes to the design of the templates to be immediately reflected throughout the application.  But modifying the design of the templates may be more difficult or impractical in the case of run time scaffolding.

===Scaffolding in Ruby on Rails===
When the line <code>scaffold :''model_name''</code> is added to a [[Ruby on Rails#Controller|controller]], Rails will automatically generate all of the appropriate data interfaces at run time.  Since the API is generated on the fly, the programmer cannot easily modify the interfaces generated this way.  Such a simple scaffold is often used for [[prototyping]] applications and entering test data into a database.

The programmer may also run an external command to generate Ruby code for the scaffold in advance: <code>rails generate scaffold ''model_name''</code>.  The <code>generate</code> script will produce files of Ruby code that the application can use to interact with the database.  It is somewhat less convenient than dynamic scaffolding, but gives the programmer the flexibility of modifying and customizing the generated APIs.

Note: As of Rails 2.0, dynamic scaffolding is no longer stored.

===Server side vs Client side Scaffolding===
Scaffolding techniques based on the application database typically involve [[Web development#Server side coding|Server side]] frameworks. Server side web frameworks commonly perform operations directly against database entries, and code generation for these operations may be considered '''Server side Scaffolding'''. Alternatively, [[Web development#Client side coding|Client side]] development often uses [[Single-page application#JavaScript Frameworks|frameworks]] that perform [[Single-page application#Data transport .28XML.2C JSON and AJAX.29|data transport]] operations instead of directly accessing the database. The focus of '''Client side Scaffolding''' is thus more on [[Yeoman (computing)|generating a starter template]] for the application as a whole, rather than generating code to access a database.

Some Client side web frameworks, such as [[Meteor (web framework)|Meteor]], allow the client to perform database operations in a manner similar to Server side frameworks. In this case, Scaffolding techniques can go beyond merely generating a starter template. They can perform [[Run time (program lifecycle phase)|run time]] scaffolding of web forms on the [[Web development#Client side coding|Client side]] to [[create, read, update and delete]] database entries. One example of this is provided by an add-on to [[Meteor (web framework)|Meteor]] called aldeed:autoform.<ref>{{Cite web|url=https://atmospherejs.com/aldeed/autoform|title = The trusted source for JavaScript packages, Meteor resources and tools &#124; Atmosphere}}</ref>

==Project generation==
Complicated software projects often share certain conventions on project structure and requirements. For example, they often have separate folders for [[source code]], [[binary files|binaries]] and [[software testing|code tests]], as well as files containing [[license agreement]]s, [[release note]]s and contact information. To simplify the creation of projects following those conventions, "scaffolding" tools can automatically generate them at the beginning of each project. Such tools include [[Yeoman (computing)|Yeoman]], [[Rust (programming language)|Cargo]] and Ritchie CLI. For [[.NET]] projects, <code>dotnet</code>, the command-line tool included with the .NET SDK, can be used to scaffold new projects.

==See also==
{{div col}}
* {{annotated link|Spring Roo}}
* {{annotated link|Play Framework}}
* {{annotated link|Apache Tapestry}}
* {{annotated link|Symfony}}
* {{annotated link|Laravel}}
* {{annotated link|Phalcon (framework)|Phalcon PHP}}
* {{annotated link|Catalyst (software)|Catalyst}}
* {{annotated link|Mojolicious}}
* {{annotated link|ASP.NET Dynamic Data}}
* {{annotated link|Ruby on Rails}}
* {{annotated link|Yii}}
* {{annotated link|CodeIgniter}}
* {{annotated link|CakePHP}}
* {{annotated link|MonoRail (software)|MonoRail}}
* {{annotated link|FuelPHP}}
* {{annotated link|Django (web framework)}}
<!--* [[KumbiaPHP]]-->
* {{annotated link|OutSystems|OutSystems Platform (PaaS)}}
* {{annotated link|Yeoman (software)|Yeoman}}
{{div col end}}

==References==
{{Reflist}}

==External links==
* [http://guides.rubyonrails.org/getting_started.html#getting-up-and-running-quickly-with-scaffolding Getting Up and Running Quickly with Scaffolding], [http://ap.rubyonrails.org/classes/ActionController/Scaffolding/ClassMethods.html Scaffolding Method Reference] (From rubyonrails.org)
* [https://web.archive.org/web/20130922114641/https://itunes.apple.com/cz/app/rails-scaffolders-toolbox/id561957238?mt=12  Rails Scaffolder's Toolbox - A GUI for the Rails Scaffolder Generators] (Mac only application, from the Mac App Store)

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[[Category:Software architecture]]
[[Category:Computer programming]]
[[Category:Types of tools used in software development]]