Scaffolding is a meta-programming method of building database-backed software applications. It is a technique supported by some model-view-controller frameworks, in which the programmer may write a specification that describes how the application database may be used. The compiler uses this specification to generate code that the application can use to create, read, update and delete database entries, effectively treating the template as a “scaffold” on which to build a more powerful application.
There are two ways to produce a scaffold in Ruby on Rails: dynamic scaffolding and scaffold generation.
When the line
scaffold :model_name is added to a controller, Ruby 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:
script/generate scaffold model_name. The
generate 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.