Persistence Entities

• Persistent Data normally refers to permanent data in an application.
• The state of these data is made permanent by storing them in a persistent medium like database, files or a disk tape.
• In JPA terms, these persistent data are referred as ENTITIES.
• An entity refers to a logical collection of data that can be stored or retrieved as a whole.

For example, in a banking application, Customer and BankAccount can be treated as entities. Customer name, customer address etc can be logically grouped together for representing a Customer entity.

• some unique characteristics

1. The property of persistability deals with the storing and retrieving of entity from and to a persistent medium like database.
2. Identity property is usually used to identity one unique entity among multiple entities (or multiple entity instances) in a database.
3. All the CRUD operations (Create, Update and Delete) for entity objects will occur within a transactional context and it is one of the major characteristic for an entity object as the real state of an entity depends whether a transaction completes (commits/fails) or not.