OneToMany Mapping

I faced this issue on August, let me explain you the situation, I had a Table called PURCHASE, with a 1:N Relationship with PURCHASE_MODULE and TRANSACTION tables

TRANSACTION >-----PURCHASE-----< PURCHASE_MODULE

First thing, How do I represent that using annotations (Hibernate): @Entity @Table(name = "PURCHASE") public class Purchase implements java.io.Serializable { @Id @Column(name = "ID", unique = true, nullable = false, insertable = true, updatable = true, precision = 10, scale = 0) public long getId() { return this.id; } ... @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY) public List<Transaction> getTransactions() { return transactions; } @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY) public List<PurchaseModule> getPurchaseModules() { return purchaseModules; } } @Entity @Table(name = "PURCHASE_MODULE") public class PurchaseModule implements java.io.Serializable { @ManyToOne(optional=false, fetch = FetchType.EAGER) @JoinColumn(name="PURCHASE_ID", referencedColumnName="id") private Purchase purchase; } @Entity @Table(name = "TRANSACTION") public class Transaction implements Serializable { @ManyToOne(optional=false, fetch = FetchType.EAGER) @JoinColumn(name="purchase_id", referencedColumnName="id") private Purchase purchase; }
Now what I want is each time I populate Purchase and set both List's (transactions and purchaseModules) and Invoke a SAVE for Purchase, the 3 tables will be impacted( there will be at least 3 INSERTs): purchaseDAO.save(purchase)
But this wasn't working as I expected, because no matter if I populated both ArrayList's (List) I never saw more than 1 Insert on my console.

Then the spark I was looking for! Inspiration came to me :P
On the Annotation @OneToMany there is an additional attribute I didn't include: cascade (The operations that must be cascaded to the target of the association)
@OneToMany(mappedBy="purchase", fetch=FetchType.LAZY, cascade=CascadeType.ALL) public List<Transaction> getTransactions() { return transactions; } @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY, cascade=CascadeType.ALL) public List<PurchaseModule> getPurchaseModules() { return purchaseModules; }
On my case I don't care, so I just include ALL operations :P

ClassCastException with Hibernate: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType

I ran into a weird error when starting a Seam App with JPA (Hibernate) on JBoss

2011-08-03 14:30:17,938 [main] ERROR [org.jboss.deployment.scanner.URLDeploymentScanner] Incomplete Deployment listing:

--- MBeans waiting for other MBeans ---
ObjectName: persistence.units:ear=mainsite.ear,jar=kaptest_domain.jar,unitName=commonDatabase
  State: FAILED
  Reason: java.lang.ClassCastException: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType
  I Depend On:
    jboss.jca:service=DataSourceBinding,name=jdbc.CommonTransactionDS
  Depends On Me:
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeMeetingDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeProductDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeUserDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AverageRatingServiceImpl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=BookstoreProductServiceImpl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=BookstoreSearchServiceImpl,service=EJB3
...
...

WHAT??? java.lang.ClassCastException: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType

Anyway, for some reason, hibernate reverse engineer puts the @Version annotation to fields called timestamp as it expects it to be of type java.sql.Timestamp
Unfortunatly, my property was of type java.util.Date which is incomaptible with the @Version annotation. @Version @Temporal(TemporalType.DATE) @Column(name = "TIMESTAMP", length = 7) private Date timestamp;
I removed the @Version and it worked! @Temporal(TemporalType.DATE) @Column(name = "TIMESTAMP", length = 7) private Date timestamp;