What is "scaffold"

Scaffold is an age-old code generation technique based on common operations templates that are used in different applications.

Contrary to what many people believe, probably fruit of having learned by cake recipe, there are several techniques to get the final result.

It is possible to accomplish this at runtime or development time, generating source codes that are aggregated to the project as if written by a person.

This technique uses a specification somewhere to generate all the necessary code based on pre-established code templates somewhere. This specification can be directly or indirectly obtained from the database, model classes or otherwise (an XML/JSON file or specific auxiliary format or even a database with a data dictionary*, for example). The rest is generated by the scaffolding tool.

The technique is best employed when this same data is used at various points in the code. But even in other situations it can be useful. Even generating code for some well-known design standards.

Also contrary to what many people think, it is not only used to make CRUD, even if it is at a point where the technique is well employed.

Reference.