Java ORM परिचय (Hibernate)

// Import javax.persistence.* so it can be used by its short name
import javax.persistence.*;
// Define the class Main
public class Main {
	@Entity
	// Define the class User
	static class User {
		@Id
		private Long id;
		private String name;
	}
	// Program entry point: the JVM starts running here
	public static void main(String[] args) {
		// Print a line to the console
		System.out.println("@Entity and @Id map this class to a table, without hand-written mapping SQL");
	}
}

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public class Main {
	// SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
	// created once per application, heavyweight, reused to open lightweight Sessions
	public static void main(String[] args) {
		System.out.println("SessionFactory compiles mappings once at startup");
	}
}

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public class Main {
	static class User { Long id; String name; }
	public static void main(String[] args) {
		User user = new User();
		user.name = "Riya";
		// session.save(user); // Hibernate converts this into an INSERT
		System.out.println("Saving " + user.name);
	}
}

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public class Main {
	static class User { Long id; String name; }
	public static void main(String[] args) {
		Long id = 1L;
		// User user = session.get(User.class, id); // translated into a SELECT
		System.out.println("Fetching User with id " + id);
	}
}

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public class Main {
	public static void main(String[] args) {
		// Transaction tx = session.beginTransaction();
		// try {
		//     session.save(new User());
		//     tx.commit();
		// } catch (Exception e) {
		//     tx.rollback(); // rolls back all related writes together
		// }
		System.out.println("Wrap persistence operations in an explicit transaction boundary");
	}
}

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