Every Magento module hosts its models within the Models directory. Some of these models are persistable, while others are non-persistable. A great deal of custom, third-party, and core Magento modules persist data to the database. Data persistence is one of the key functionalities that platforms like Magento need to deal with. Terminology-wise, Magento uses terms such as model, resource model, and collection for a group of three classes that deal with data persistence, that is, create, read, update, and delete (CRUD) operations.

To better understand the overall mechanism of entities, we are going to take a closer look at the following:

• Understanding types of models:
  • Creating a simple model
  • Methods worth memorizing
• Working with setup scripts:
  • The InstallSchema script
  • The UpgradeSchema script
  • The Recurring script
  • The InstallData script
  • The UpgradeData script
  • The RecurringData script
• Creating extension attributes