Re: [eclipselink-users] Partitioning with unidirectional associations

[Mike Key <mikey@xxxxxxxxxxx>]

I think my question should be expanded a bit as I've run across a curious situation.  I'm trying to model something after the example found on:

http://wiki.eclipse.org/EclipseLink/Examples/JPA/Partitioning

I have a slightly more simplistic example.  My persistence unit looks like:

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"; version="2.0">
  <persistence-unit name="sample" transaction-type="RESOURCE_LOCAL">
    <class>samples.model.EmailAddress</class>
    <class>samples.model.Customer</class>
    <properties>
      <property name="javax.persistence.jdbc.driver"
                value="com.mysql.jdbc.Driver"/>
      <property name="javax.persistence.jdbc.url"
                value="jdbc:mysql://localhost:3306/defaultdb"/>
      <property name="javax.persistence.jdbc.user" value="defaultdb"/>
      <property name="javax.persistence.jdbc.password" value="defaultdb"/>

      <!-- Configure default connection pool. -->
      <property name="eclipselink.connection-pool.default.initial" value="1"/>
      <property name="eclipselink.connection-pool.default.min" value="64"/>
      <property name="eclipselink.connection-pool.default.max" value="64"/>

      <!-- Configure 2nd database connection pool. -->
      <property name="eclipselink.connection-pool.node2.url"
                value="jdbc:mysql://localhost:3306/node2"/>
      <property name="eclipselink.connection-pool.node2.user" value="node2"/>
      <property name="eclipselink.connection-pool.node2.password"
                value="node2"/>
      <property name="eclipselink.connection-pool.node2.initial" value="1"/>
      <property name="eclipselink.connection-pool.node2.min" value="64"/>
      <property name="eclipselink.connection-pool.node2.max" value="64"/>

      <!-- Default partioning to replication to allow DDL to be sent to all nodes -->
      <property name="eclipselink.partitioning" value="Replicate"/>
    </properties>
  </persistence-unit>
</persistence>

Customer has the following partitions and OneToMany to EmailAddress:

@Entity
@Table(name = "customer")
@UnionPartitioning(
        name = "UnionPartitioningAllNodes",
        replicateWrites = true,
        connectionPools = {"default", "node2"})
@ReplicationPartitioning(name="Replicate", connectionPools={"default","node2"})
@HashPartitioning(name="HashPartitionByCustomerNamespace", partitionColumn=@Column(name="NAMESPACE"), connectionPools={"default","node2"}, unionUnpartitionableQueries = true)
@Partitioned("HashPartitionByCustomerNamespace")
public class Customer implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private int namespace = 0;

    private String firstName;

    private String lastName;

    @OneToMany(mappedBy = "customer", cascade = CascadeType.ALL)
    private List<EmailAddress> emailAddresses = new ArrayList<EmailAddress>();


EmailAddress then has:

@Entity
@Table(name = "email_address")
@HashPartitioning(name="HashPartitionByEmailNamespace", partitionColumn=@Column(name="NAMESPACE"), connectionPools={"default","node2"}, unionUnpartitionableQueries = true)
@Partitioned("HashPartitionByEmailNamespace")
public class EmailAddress {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String address;

    private String type;

    private int namespace = 0;

    @ManyToOne
    private Customer customer;

I have a simple test that just creates a new Customer and adds an email address and then I try to persist this.

The hash passes in simple 0 or 1 in namespace to determine which datastore to save the record in.  If I try to persist Customer in one datastore and EmailAddress in the other, I get the following:

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`default`.`email_address`, CONSTRAINT `FK_email_address_CUSTOMER_ID` FOREIGN KEY (`CUSTOMER_ID`) REFERENCES `customer` (`ID`))

I would assume this would work as the sample code at the link above seems to suggest.  Is there something I am doing wrong here that is obvious?  I should note I am creating the entity manager via Spring as follows:

 <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="sample"/>
    <property name="persistenceProvider" ref="eclipseLinkPersistenceProvider"/>
    <property name="jpaVendorAdapter">
      <bean
          class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
        <property name="databasePlatform"
                  value="org.eclipse.persistence.platform.database.MySQLPlatform"/>
        <property name="showSql" value="true"/>
        <property name="generateDdl" value="true"/>
      </bean>
    </property>
  </bean>

Thanks in advance for the help.

Mike Key

  
On Mar 22, 2012, at 1:59 PM, Mike Key wrote:

> Forgive me if this has been answered here already.  I am setting up some partitioning schemes in Eclipselink 2.3.2 with JPA.  It would seem my simple example will only work for One-To-Many relationships if the association is bi-directional.  Is this by design?  It seems to make sense logically that it is, however I am wondering if uni-directional associations are supported in any way for partitioning?
> 
> Thanks for any help.
> 
>

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