Implementing Auto generated PK

[nmaia]

I'm trying to implement in Jboss 3.2 Beta auto generated PK. I already saw the post http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t=forums/ but jboss give a lot of errors when I inserted the auto generated PK. A looked at the Jboss source test suite and JBoss.3.0TemplateAndExamples.zip to see if there was a sample and noting. If anyone was accomplished that could send a sample.

Thanks a Lot

Nuno Maia

[aloubyansky]

To make sure the jboss version you use supports generated by db pk values, check jbosscmp-jdbc_3_0.dtd. There should be unknown-pk element in entity element.
If there is and you tried to configure it with the reference you mentioned and have troubles, then post the details and I'll help you.

[nmaia]

Really the unknown-pk has not in jboss 3.2 beta that I had downloaded from sourceforge.net. Since I having some trouble compiling the CVS version of Jboss. There is any Jboss binary version that I can download that supports unknown-pk.


Thanks again for you time

Nuno Maia

[rupinder]

i too have a similar requirement.

i am using JBoss 3.0.3 integrated with Tomcat4.1.12 and my database is Oracle 8.1.7
i need to know can i use the Sequence of Oracle as we can do in Weblogic for automatic primary key generation for CMP's.

i checked the jbosscmp-jdbc_3_0.dtd that was provided with this downloaded version of JBoss.There is no unknown-pk element in this dtd.Does this mean automatic key generation cannot be used with JBoss 3.0.3 ?
With what version of Jboss can i use this feature with Oracle?

thanks,
Rupinder

[bernd.koecke]

With a cvs-checkout of module 'jboss-3.2' and Tag 'Branch_3_2' you can compile a JBoss-Version which uses unknown primary keys. I don't had any problems compiling the source. I was really impressed that it works out of the box (cvs). And I have the unknown-pk element in jbosscmp-jdbc_3_0.dtd after checkout.

In my test environment the jbosscmp-jdbc-file was build like the example in the above noted thread. My Test-DBMS is PostgreSQL, but I use a normal SQL-Command for getting the PK. The only requirement is, that the PK could be fetched before the row is written to the DB (e.g. with a sequence). I think it is not possible to use a PK which was generated by the DB at Insertion. Because you can't fetch the PK-column after the insert to fill the bean PK-field.

I don't know if the unknownPK feature will be backported to JBoss 3.0.x, I'm not a JBoss-Developer. I think this feature was first introduced by Alex Loubyansky for JBoss 3.2.

Bernd

[nmaia]

I had compiled Jboss, thanks for you support. But I have one more question.

The deployment does't give more errors. But when I create a new bean is gives a error.

The jbosscmp-jdbc.xml bean.


<entity>
<ejb-name>Lixo</ejb-name>
<table-name>lixo</table-name>


<cmp-field>
<field-name>name</field-name>
<column-name>name</column-name>
</cmp-field>

<unknown-pk>
<unknown-pk-class>java.lang.Long</unknown-pk-class>
<field-name>id</field-name>
<column-name>id</column-name>
</unknown-pk>

<entity-command name="pk-sql">
<attribute name="pk-sql">select nextval ('lixo_id_seq');</attribute>
</entity-command>

</entity>


The bean code

public Long ejbCreate(Long id, String name) throws CreateException {
setId(id);
setName(name);
return id;
}

public void ejbPostCreate(Long id, String name) {
}


When I call the ejcCreate with a Long that Long is assigned to the bean Instead of sql sequence, if the id is called with a null value it gives a null error. Every time that bean is created the Postgresql is incrementing the sequence

Thanks

[aloubyansky]

You don't have to call setId() in this case at all.
Actually, I think setId() shouldn't affect the correct bean creation. Do you have id declared as a cmp-field in ejb-jar.xml? If yes, then remove it. It's unknown primary key.

[aloubyansky]

And no abstract accessors for id too.

[nmaia]

I had already done that and I got another error. But the sequence continues to be incremented.

The trace


1:11:14,145 ERROR [Lixo] Error checking if entity exists
java.sql.SQLException: ERROR: parser: parse error at or near ""

at org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:94)
at org.postgresql.Connection.ExecSQL(Connection.java:398)
at org.postgresql.jdbc2.Statement.execute(Statement.java:130)
at org.postgresql.jdbc2.Statement.executeQuery(Statement.java:54)
at org.postgresql.jdbc2.PreparedStatement.executeQuery(PreparedStatement.java:99)
at org.jboss.resource.adapter.jdbc.local.LocalPreparedStatement.executeQuery(LocalPreparedStatement.java:289)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCCreateEntityCommand.entityExists(JDBCCreateEntityCommand.java:168)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCPkSqlCreateCommand.execute(JDBCPkSqlCreateCommand.java:241)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.createEntity(JDB

[aloubyansky]

Verify the following:
ejb-jar.xml
- prim-key-class is java.lang.Object
- no cmp-field for id
- no primkey-field

jbosscmp-jdbc.xml looks ok.

ejbCreate method should return java.lang.Object;
findByPrimaryKey should take the param of type Object.
Though, as to the last two, you can try to set other types. I am not sure though. But according to the spec, it should be Object.

[bernd.koecke]

You asked for my config, so here it is. Look at the part for the PersonCmp-Bean, its the smallest one.

I use the name of the upk field only in container managed relationships. As Alex noted I have no field definition and no accessor methods for the upk field and I did all the other things Alex mentioned in his posting.

There are two differences between your and my SQL statement. I don't have a ';' at the end and it seems that you have a space between 'nextval' and '('. I think thats why you get this exception with an empty string.

Bernd

[nmaia]

It worked. Thanks to all who helped me.
And I have a final question and only answer if you want. But it's possible to know the last auto genereted PK.


Thanks to all
Nuno Maia

[bernd.koecke]

You could do "select currval('seqname')" (Chapter 4.11 of PostgreSQL 7.2 user manual). Then you will get the last given value of the sequence, but it is only defined after a call to 'nextval' in the same process/transaction and you will get the generated and used value.

Another solution is to call 'select last_value from seqname', but then you don't know for which entity it was used.

But in an EJB-System you could call getPrimaryKey() on the local or remote interface and cast it to your declared type.

Bernd

[rupinder]

Hi,

i am unable to do cvs-checkout of jboss-3.2.0 because of firewall issues.
I need to know will it work if i just get the jbosscmp-jdbc_3_0.dtd having unknown-pk and replace the dtd i have in the downloaded version(which is not a cvs-checkout).
If yes, can somebody provide me this dtd.

thanks
Rupinder

[rupinder]

Hi,

i am unable to do cvs-checkout of jboss-3.2.0 because of firewall issues.
I need to know will it work if i just get the jbosscmp-jdbc_3_0.dtd having unknown-pk and replace the dtd i have in the downloaded version(which is not a cvs-checkout).
If yes, can somebody provide me this dtd.

thanks
Rupinder