An entity is a Java object whose state is persisted in a database through object-relational mapping. In Quarkus, mark the class with `@Entity`, then choose where persistence operations belong: on the entity with Panache’s active record pattern, in a repository, or in code using JPA’s `EntityManager`. section 7.1.2 section 7.2.1 section 7.3
The entity definition changes with the access pattern:
- For active record, extend `PanacheEntity`. The reservation entity inherits an ID and can define a static query method such as `findByCar(carId)` alongside its fields and business behavior. section 7.1.2
- For a repository, a plain JPA entity is enough. The car entity declares its own `@Id` and `@GeneratedValue` field; an `@ApplicationScoped` class implementing `PanacheRepository<Car>` handles persistence access. section 7.2.1
- For traditional JPA access, define entities as usual and inject `EntityManager` into a CDI bean. Panache is not required for this approach. section 7.3
Listing 7.5 The Reservation entity in the Reservation service
package org.acme.reservation.entity;
import io.quarkus.hibernate.orm.panache.PanacheEntity;
import jakarta.persistence.Entity;
import java.time.LocalDate;
@Entity
public class Reservation extends PanacheEntity {
public Long carId;
public String userId;
public LocalDate startDay;
public LocalDate endDay;
/**
* Check if the given duration overlaps with this reservation
* @return true if the dates overlap with the reservation, false
* otherwise
*/
public boolean isReserved(LocalDate startDay, LocalDate endDay) {
return (!(this.endDay.isBefore(startDay) ||
this.startDay.isAfter(endDay)));
}
@Override
public String toString() {
return "Reservation{" +
"id=" + id +
", carId=" + carId +
", userId='" + userId + '\'' +
", startDay=" + startDay +
", endDay=" + endDay +
'}';
}
}
The reservation class shows `@Entity` on a `PanacheEntity` subclass with application fields and an overlap-checking method. section 7.1.2
Listing 7.13 The Car entity
package org.acme.inventory.model;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
@Entity
public class Car {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String licensePlateNumber;
private String manufacturer;
private String model;
// getters, setters, toString, equals, and hashcode omitted
}
The car class shows the alternative: a plain JPA entity with an explicitly declared, generated primary key. section 7.2.1
To persist these entities, add the Hibernate ORM extension for the chosen approach and a JDBC driver for the database, then configure the datasource in `application.properties`. The examples use PostgreSQL for reservations and MySQL for inventory. Their `drop-and-create` schema setting drops and recreates the database schema at startup, so it is not a setting to carry over unexamined to production. section 7.1.2 section 7.2.1 section 7.3
