Hi there,

I hope it's not a misuse of Hibernate, but I'm trying to use @Id on @OneToOne, and this causes the following NPE when running hbm2ddl:



What I'm trying to do at the application level is:




This is expressed in Java as:



This causes a NPE here.

If I use a real Id on FooData, e.g.:

it works, and I end up with:
- foo_id in table foo as a primary key
- foo_data_id in table foo_data as a primary key
- foo_id in table foo_data not null
- foo_id in table foo_data references foo_id in table foo

This would be almost perfect except... I don't want a foo_data_id, I don't need it.

How can I express that my @OneToOne is also the @Id?

Thanks,

--
Loïc Minier

This construct is not possible in Hibernate, what you can do is



It's better to use the Hibernate annotations forum for such questions, I don't follow the Hibernate Users one much :-)

Ah this sounds like a good workaround, thanks!

Unfortunately, this results in a quite similar NPE (I think it's the same).

--
Loïc Minier

I don't get a NPE when I apply my advice

I still get the NPE; but I know what differs between your environment and mine, this is the NPE I get:
build.xml:406: java.lang.NullPointerException
at org.hibernate.tool.ant.HibernateToolTask.reportException(HibernateToolTask.java:211)
at org.hibernate.tool.ant.HibernateToolTask.execute(HibernateToolTask.java:174)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
at org.apache.tools.ant.Task.perform(Task.java:364)
at org.apache.tools.ant.Target.execute(Target.java:341)
at org.apache.tools.ant.Target.performTasks(Target.java:369)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1216)
at org.apache.tools.ant.Project.executeTarget(Project.java:1185)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:40)
at org.apache.tools.ant.Project.executeTargets(Project.java:1068)
at org.apache.tools.ant.Main.runBuild(Main.java:668)
at org.apache.tools.ant.Main.startAnt(Main.java:187)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67)
Caused by: java.lang.NullPointerException
at org.hibernate.cfg.OneToOneSecondPass.doSecondPass(OneToOneSecondPass.java:135)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1130)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:296)
at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1115)
at org.hibernate.tool.ant.ConfigurationTask.getConfiguration(ConfigurationTask.java:56)
at org.hibernate.tool.ant.HibernateToolTask.getConfiguration(HibernateToolTask.java:287)
at org.hibernate.tool.ant.Hbm2DDLExporterTask.execute(Hbm2DDLExporterTask.java:45)
at org.hibernate.tool.ant.HibernateToolTask.execute(HibernateToolTask.java:171)
... 12 more
--- Nested Exception ---
java.lang.NullPointerException
at org.hibernate.cfg.OneToOneSecondPass.doSecondPass(OneToOneSecondPass.java:135)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1130)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:296)
at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1115)
at org.hibernate.tool.ant.ConfigurationTask.getConfiguration(ConfigurationTask.java:56)
at org.hibernate.tool.ant.HibernateToolTask.getConfiguration(HibernateToolTask.java:287)
at org.hibernate.tool.ant.Hbm2DDLExporterTask.execute(Hbm2DDLExporterTask.java:45)
at org.hibernate.tool.ant.HibernateToolTask.execute(HibernateToolTask.java:171)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
at org.apache.tools.ant.Task.perform(Task.java:364)
at org.apache.tools.ant.Target.execute(Target.java:341)
at org.apache.tools.ant.Target.performTasks(Target.java:369)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1216)
at org.apache.tools.ant.Project.executeTarget(Project.java:1185)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:40)
at org.apache.tools.ant.Project.executeTargets(Project.java:1068)
at org.apache.tools.ant.Main.runBuild(Main.java:668)
at org.apache.tools.ant.Main.startAnt(Main.java:187)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67)

With:

@Entity
@Table(name = "accounts")
public class Account {
@Id @GeneratedValue
@Column(name = "account_id")
Long id;

@OneToOne(mappedBy = "account", cascade = CascadeType.ALL)
AccountData accountData;

@Entity
@Table(name = "accounts_data")
public class AccountData {
@Id
@Column(name = "account_id", nullable = false)
Long id;

@OneToOne
@JoinColumn(name = "account_id", nullable = false, insertable = false, updatable = false)
Account account;
...


I don't get the NPE if I remove the @OneToOne from Accounts (which is mappedBy, so reversed IIUC).

Can you confirm you get the NPE with the mappedBy @OneToOne?

use branch_3_2

I'm also seeing this NPE when deploying my app. I'm using Hibernate 3.2.2GA, I have three tables:

CREATE TABLE user_table
(
user_id varchar(50) not null primary key,
password varchar (32)
);

CREATE TABLE partner
(
id INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,
partner_name VARCHAR(50) NOT NULL UNIQUE
);

CREATE TABLE user_partner_mapping
(
id INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,
user_id varchar(50) not null unique,
partner INTEGER NOT NULL -- Foreign key into partner
);

ALTER TABLE user_partner_mapping ADD CONSTRAINT FK_mapping_user
FOREIGN KEY FK_mapping_user (user_id)
REFERENCES user_table (user_id)
ON DELETE RESTRICT
ON UPDATE RESTRICT;

ALTER TABLE user_partner_mapping ADD CONSTRAINT FK_mapping_partner
FOREIGN KEY FK_mapping_partner (partner)
REFERENCES partner (id)
ON DELETE RESTRICT
ON UPDATE RESTRICT;


I used Netbeans to auto-generate entity beans for these tables, and it came up with:

UserTable:

@Id
@Column(name = "user_id", nullable = false)
private String userId;

@Column(name = "password")
private String password;

@OneToOne(mappedBy = "controlPointUserId")
private ControlPoint controlPoint;

@OneToOne(cascade = CascadeType.ALL, mappedBy = "userId")
private UserPartnerMapping userPartnerMapping;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "userId")
private Collection<UserControlPointMapping> userControlPointMappingCollection;

@OneToOne(cascade = CascadeType.ALL, mappedBy = "userId")
private Customer customer;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "userId")
private Collection<GroupTable> groupTableCollection;


=============
Partner:

@Id
@Column(name = "id", nullable = false)
private Integer id;

@Column(name = "name", nullable = false)
private String name;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "partner")
private Collection<Bundle> bundleCollection;


==============
UserPartnerMapping:
@Id
@Column(name = "id", nullable = false)
private Integer id;

@Column(name = "partner", nullable = false)
private int partner;

@JoinColumn(name = "user_id", referencedColumnName = "user_id")
@OneToOne
private UserTable userId;


Any suggestions?



[list=][/list]

use Hibernate Annotations 3.3.0