Optimisation des requêtes JPQL : Persistance des objets

Voici un exemple d'utilisation de la méthode persist :
EntityTransaction trans = entityManager.getTransaction();
trans.begin(); // Début de la transaction
User user = new User( "Bond", "James", 007 );
entityManager.persist( user ); // Les ordres SQL sont produits au fil des persists
Command theCommand = new Command( user, new Date() );
Set<CommandLine> lines = theCommand.getLines();
Article article1 = new Article( "Truc de fou", "La marque qui tue", 100 );
entityManager.persist( article1 );
Article article2 = new Article( "Truc de dingue", "Autre marque qui tue", 200 );
entityManager.persist( article2 );
CommandLine line1 = new CommandLine( article1, theCommand, 2 );
lines.add( line1 );
CommandLine line2 = new CommandLine( article2, theCommand, 3 );
lines.add( line2 );
entityManager.persist( theCommand );
System.out.println( "Now == flush" );
entityManager.flush();
trans.commit()

Si vous avez activé les logs sur les requêtes SQL générées, voici ce qui sera produit :

[main] DEBUG | org.hibernate.SQL | insert into T_Users (Login, Password, ConnectionNumber) values (?, ?, ?) (SQLStatementLogger.java:111)

[main] DEBUG | org.hibernate.SQL | insert into T_Commands (IdUser) values (?) (SQLStatementLogger.java:111)

[main] DEBUG | org.hibernate.SQL | insert into T_Articles (Description, Brand, UnitaryPrice) values (?, ?, ?) (SQLStatementLogger.java:111)

[main] DEBUG | org.hibernate.SQL | insert into T_CommandLines (IdArticle, Quantity) values (?, ?) (SQLStatementLogger.java:111)

[main] DEBUG | org.hibernate.SQL | insert into T_Articles (Description, Brand, UnitaryPrice) values (?, ?, ?) (SQLStatementLogger.java:111)

[main] DEBUG | org.hibernate.SQL | insert into T_CommandLines (IdArticle, Quantity) values (?, ?) (SQLStatementLogger.java:111)

Now == flush

[main] DEBUG | org.hibernate.SQL | insert into T_CommandLinesMapping (IdCommand, IdCommandLine) values (?, ?) (SQLStatementLogger.java:111)

Améliorations / Corrections