Explain the concept of code-first and database-first approaches in Entity Framework.

In Entity Framework, the code-first approach involves defining your domain classes first and then letting EF generate the database schema based on those classes. This is useful when you want to focus on your application's domain logic. On the other hand, the database-first approach involves designing your database schema first and then generating corresponding domain classes from that schema. This can be handy when working with an existing database.