We have seen Code-first, Model-first and Database-first approaches in the previous sections. So, now you have to make a decision about which development approach to use in your application. The following figure illustrates the decision tree.
As per the above figure, if you already have an existing application with domain classes, then you can use the code-first approach because you can create a database from your existing classes in this approach. If you have an existing database, then you can create an EDM from an existing database in the database-first approach. If you do not have an existing database or domain classes, and you prefer to design your DB model on the visual designer, then go for Model-first approach.