Re: Unecessary database update?
Alain -
I looked at your unit test and the reason that an extra update is being
sent to the database is because you're updating your Entity in the
@PreUpdate method. If you didn't update that field, no update would be
issued. That being said, I think we're getting down to the real problem.
I don't think @PreUpdate should be called in this instance because even
though Parent is dirty, it doesn't result in a DB update and as such,
@PreUpdate shouldn't be invoked. I thought we had a feature to control this
behavior, but I'm struggling to find it right now.
I'll attach my unit test for future reference.
Thanks,
Rick
On Tue, Mar 25, 2014 at 9:22 AM, Alain Brazeau abraz...@rogers.com wrote:
Hi Rick,
As requested, here is a test I wrote in the 'openjpa-persistence-jdbc'
project:
package org.apache.openjpa.persistence.jdbc.update;
import java.util.Date;
import javax.persistence.EntityManager;
import org.apache.openjpa.persistence.test.SingleEMFTestCase;
public class TestCascadePersist extends SingleEMFTestCase {
public void setUp() throws Exception {
super.setUp(CLEAR_TABLES, Parent.class, Child.class);
}
public void testAddChildShouldNotUpdateParent() {
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
Parent parent = new Parent();
parent.setName(parent);
em.persist(parent);
em.getTransaction().commit();
long parentId = parent.getId();
Date expectedLastModifiedDate = parent.getLastModifiedDate();
em.getTransaction().begin();
parent = em.find(Parent.class, parentId);
parent.newChild(child);
em.getTransaction().commit();
Date actualModifiedDate = parent.getLastModifiedDate();
assertEquals(The last modified date should not change.,
expectedLastModifiedDate.getTime(),
actualModifiedDate.getTime());
}
}
In order for the test to work, the following instance variable and methods
have to be added to the
existing org.apache.openjpa.persistence.jdbc.update.Parent class:
private Date lastModifiedDate;
public Date getLastModifiedDate() {
return lastModifiedDate;
}
@PrePersist
@PreUpdate
public void onUpdate() {
this.lastModifiedDate = new Date();
}
Thanks!
Alain
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*Rick Curtis*
Re: Unecessary database update?
Hi Rick,
As requested, here is a test I wrote in the 'openjpa-persistence-jdbc'
project:
package org.apache.openjpa.persistence.jdbc.update;
import java.util.Date;
import javax.persistence.EntityManager;
import org.apache.openjpa.persistence.test.SingleEMFTestCase;
public class TestCascadePersist extends SingleEMFTestCase {
public void setUp() throws Exception {
super.setUp(CLEAR_TABLES, Parent.class, Child.class);
}
public void testAddChildShouldNotUpdateParent() {
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
Parent parent = new Parent();
parent.setName(parent);
em.persist(parent);
em.getTransaction().commit();
long parentId = parent.getId();
Date expectedLastModifiedDate = parent.getLastModifiedDate();
em.getTransaction().begin();
parent = em.find(Parent.class, parentId);
parent.newChild(child);
em.getTransaction().commit();
Date actualModifiedDate = parent.getLastModifiedDate();
assertEquals(The last modified date should not change.,
expectedLastModifiedDate.getTime(),
actualModifiedDate.getTime());
}
}
In order for the test to work, the following instance variable and methods
have to be added to the
existing org.apache.openjpa.persistence.jdbc.update.Parent class:
private Date lastModifiedDate;
public Date getLastModifiedDate() {
return lastModifiedDate;
}
@PrePersist
@PreUpdate
public void onUpdate() {
this.lastModifiedDate = new Date();
}
Thanks!
Alain
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View this message in context:
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Re: Unecessary database update?
Can you put together a small unit test[1] that recreates the issue?
[1] https://openjpa.apache.org/writing-test-cases-for-openjpa.html
Thanks,
Rick
On Sat, Mar 22, 2014 at 6:53 PM, Alain Brazeau abraz...@rogers.com wrote:
My application has the following bidirectional one-to-many association:
@Entity
@Table(name=TB_CUSTOMERS)
public class Customer {
@OneToMany(mappedBy=customer, cascade={CascadeType.PERSIST,
CascadeType.REMOVE})
@OrderBy(createdDate DESC)
private ListOrder orders = new ArrayListOrder();
...
}
@Entity
@Table(name=TB_ORDERS)
public class Order {
@ManyToOne
@JoinColumn(name=CUSTOMER_ID)
private Customer customer;
...
}
I recently noticed that when a new Order object is added to a Customer
object's Order List, the underlying Customer database table record gets
updated, even though the Customer object was not modified. This is
especially problematic since I have a database trigger defined on the
Customer table that inserts the old version of a record in a Customer
history table for auditing purposes whenever an update occurs.
I am currently using OpenJPA version 2.0.1. I have tried upgrading to
version 2.2.2, but still have the same problem. If I use Hibernate instead
of OpenJPA as the JPA implementation, the Customer database table does NOT
get updated.
Based on my understanding of JPA, the Customer record should not get
updated
unless LockModeType.OPTIMISTIC_FORCE_INCREMENT is used (for optimistic
locking).
In case it matters, I am using build time enhancement. Here is the
relevant
section from my Maven pom.xml file:
plugin
groupIdorg.apache.openjpa/groupId
artifactIdopenjpa-maven-plugin/artifactId
version${openjpa.version}/version
configuration
addDefaultConstructortrue/addDefaultConstructor
/configuration
executions
execution
idenhancer/id
phaseprocess-classes/phase
goals
goalenhance/goal
/goals
/execution
/executions
dependencies
dependency
groupIdorg.apache.openjpa/groupId
artifactIdopenjpa/artifactId
version${openjpa.version}/version
/dependency
/dependencies
/plugin
Any help or advice would be greatly appreciated.
Thanks,
Alain
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*Rick Curtis*
