<class name="hTest.User" table="User">
<id name="CategoryId" column="CategoryId" unsaved-value ="0">
<generator class="native" />
</id>
<property name="Name" column="Name" />
<joined-subclass name="hTest.AdvUser" table="AdvUser" lazy="true">
<key column="Address_Id"/>
<property name="info" column="info"/>
</joined-subclass>
</class>


In the code,
User c = new User();
c.Name = "xxx";
...
session.Save(c);
...

AdvUser c = new AdvUser();
c.Name = "xxx22";
c.info = "xxx22";
...
session.Save(c);

It works fine, I can save whatever I want ,
and it works on AdvUser


However IF the table is empty
then I just create AdvUser,
It will keep overwrite the Id =1 record,
it wont save a new one

but after I create User, then save back , the database works fine again, it seems strange to me, any idea

Does anyone have this problem ?

The behaviour of "native" generator depends on database in use, so explanation would depend on that.

But assuming MS SQL, the Id of saved object is whatever the CategoryId identity column of table User returns after insert.

Gert

I am usiny MySQL ,

NHibernate: INSERT INTO User(Name) VALUES (?p0)
?p0 = 'Test Name'
NHibernate: SELECT LAST_INSERT_ID()
NHibernate: INSERT INTO AdvUser(info, Address_Id) VALUES (?p0, ?p1)
?p0 = 'TESTInfo'
?p1 = '1'

I always get Id = 1 , on get next id

However , If i only insert User , (not AdvUser)
I will get ?p1='2'

AFAIK NHibernate uses the value returned by this as an ID. So, it is up to Your database server do return correct value.

Gert

If you are using 1.2.0.Beta3, try upgrading to CR1. There was a bug in Beta3 that caused "SELECT LAST_INSERT_ID()" to execute in a different connection/transaction than the actual insert statement so last_insert_id() could return a wrong value.

I updated into CR1

the problem come worse ,

even I created the base object
User c = new User();

it will keep overwrite the exisitng one

Post your class definitions please, both User and AdvUser.

I set hbm2ddl.auto into hibernatae.cfg.xml

<property name="hbm2ddl.auto">create</property>

it seems to create the table everytime ?

because I disable this property, it works ,

any idea how to use hbm2ddl.auto ?

I want to create the table in the 1st time insert

User.hbm.xml
----------------
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" assembly="digi">
<class name="hTest.User" table="User">
<id name="UserId" column="UserId" unsaved-value ="0">
<generator class="native" />
</id>
<property name="Name" column="Name" />

<joined-subclass name="hTest.AdvUser" table="AdvUser" lazy="true">
<key column="AdvUser_Id" foreign-key="UserId"/>
<property name="Info" column="Info"/>
</joined-subclass>
</class>
</hibernate-mapping>

--------------------------------------------
User.cs

public class User
{
private int _userId;
private string _name;

public virtual string UserId
{
get { return _userId; }
set { _userId = value; }
}

public virtual string Name
{
get { return _name; }
set { _name = value; }
}

}
--------------------------------------------


AdvUser.cs
------------
public class AdvUser: User
{
private string _info;

public AdvUser()
{
}

public virtual string Info
{
get { return _info; }
set { _info = value; }
}
}

I assume that "public virtual string UserId" is a typo.

hbm2ddl.auto creates tables when the session factory is first created. It seems to me that you are creating more than one session factory in your code, that is unnecessary.

here is the main program ,
I run the program in command line to test


Helper.cs
---------
public class Helper
{
public static string strLoggerCfg = "digi";
public static string strHibernateCfg = "digi";
private static ISessionFactory sessionFactory;
private static Configuration configuration;
private static readonly ILog logger = LogManager.GetLogger(strLoggerCfg);

/*
* Get Hibernate Factory
* getSessionFactory()
* - return ISessionFactory
*/
public static ISessionFactory getSessionFactory(){
try {
if ( sessionFactory == null ){
sessionFactory = getConfiguration().BuildSessionFactory();
}
return sessionFactory;
}
catch (HibernateException e){
getLogger().Fatal("--getSessionFactory()--");
getLogger().Fatal(e.ToString());
return null;
}
}

/*
* Get Hibernate Configuration
* getConfiguration()
* - return Configuration
*/
public static Configuration getConfiguration(){
try{
if (configuration == null){
configuration = new Configuration()
.Configure()
.AddAssembly(strHibernateCfg);
}
return configuration;
}
catch( HibernateException e){
getLogger().Fatal("--getConfiguration()--");
getLogger().Fatal(e.ToString());
return null;
}
}
public static ILog getLogger()
{
XmlConfigurator.Configure();
return logger;
}
}


Program.cs
----------
static void Main(string[] args)
{
ILog logger = Helper.getLogger();

User c = new User();
c.Name = "xxx";

try
{
ISession session = Helper.getSessionFactory().OpenSession();

ITransaction transaction = session.BeginTransaction();

session.Save(c);
transaction.Commit();
session.Close();
}
catch (HibernateException e)
{
logger.Fatal(e.ToString());
}
}