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From "Pinaki Poddar" <>
Subject RE: [jira] Created: (OPENJPA-245) Attach NEW and auto-increment identity
Date Mon, 28 May 2007 05:15:25 GMT
>> just create a new instance of an entity, assign an already existing
primary key
>> A new record will be created in database, with new, auto-generated
primary key.

What is the identity mechanicsm used by the entity class? 
If the entity is using auto-generated identity then assigning an
"already existing" key is not recommneded. 
If the entity is not using auto-generated, then assigning an existing
key *should* fail at commit with duplicate key exception.  

Pinaki Poddar
BEA Systems

-----Original Message-----
From: Aleksandar Likic (JIRA) [] 
Sent: Sunday, May 27, 2007 9:05 AM
Subject: [jira] Created: (OPENJPA-245) Attach NEW and auto-increment

Attach NEW and auto-increment identity

                 Key: OPENJPA-245
             Project: OpenJPA
          Issue Type: Bug
          Components: jpa
    Affects Versions: 0.9.7, 0.9.6
         Environment: jdk1.5.0_11, Win XP, Fedora Core 6, Postgres 8.1
(on Fedora)
            Reporter: Aleksandar Likic

According to documentation (1.2 Attach Behavior), when an entity
instance is NEW (never detached):

    * If neither of the above cases apply, OpenJPA will check to see if
an instance with the same primary key values exists in the database. If
so, the object is considered detached. Otherwise, it is considered new.

This doesn't work for me - a new record in database is created on commit
instead of updating the existing one. The "regular" case -
detach/modify/attach works fine - the existing record is updated.

It is very easy to reproduce - just create a new instance of an entity,
assign an already existing primary key, call em.merge() and commit. A
new record will be created in database, with new, auto-generated primary

I stumbled on this trying to implement a web service that uses
OpenJPA-based backend. When servicing an "update" request, the web
service instantiates a NEW object (by performing XML de-serialization)
and calls em.merge to update the entity. A new record gets created
instead of updating an existing one.

------------ Entity class (START) ------------------------------

package exaple;

public class Consumer implements {

  private long id;

  public long getId() {

  public void setId(long id) { = id;

  private java.lang.String firstName;

  public java.lang.String getFirstName() {
    return this.firstName;

  public void setFirstName(java.lang.String firstName) {
    this.firstName = firstName;

  private java.lang.String lastName;

  public java.lang.String getLastName() {
    return this.lastName;

  public void setLastName(java.lang.String lastName) {
    this.lastName = lastName;

------------ Entity class (END) ------------------------------
------------ persistence.xml (START) ------------------------------
<?xml version="1.0" encoding="UTF-8"?> <persistence
xmlns:xsi="" version="1.0">

    <persistence-unit name="example" transaction-type="RESOURCE_LOCAL">

        <!-- We must enumerate each entity in the persistence unit -->


            <property name="openjpa.jdbc.DBDictionary"
            <property name="openjpa.ConnectionDriverName"
            <property name="openjpa.ConnectionUserName"
            <property name="openjpa.ConnectionPassword"
            <property name="openjpa.ConnectionURL"
            <property name="openjpa.Log"
------------ persistence.xml (END) ------------------------------
------------ orm.xml (START) ------------------------------
<entity-mappings xmlns="" 
    <entity class="example.Consumer">
            <id name="id">
                <generated-value strategy="IDENTITY"/>
            <basic name="firstName">
                <column name="first_name"/>
            <basic name="lastName">
                <column name="last_name"/>
------------ orm.xml (END) ------------------------------

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