In the ASP.NET MVC framework, the code-first approach is a development model where you first write the code that creates the data access layer, then you write the code that creates the controllers and views. In the code-first approach, you create a model, which is a class that represents the data in the application. Then you create a data access layer, which is a set of code that reads and writes data to a data store. Note that a code-first approach does not have to use a database. You could use the code-first model to create any kind of data.