Many-to-Many relationship with cmp

[dharfleet]

Hi,

I have three entities:

I have three database tables, say for example:

USER, ROLE and USER_ROLE

USER and ROLE both have a pk and USER_ROLE uses the pk from USER and ROLE to map the many to many relationship.

I want to use CMP, but want to make sure I still have the third table (USER_ROLE) created by jaws.

I will be using a session facade, but would still prefer to manage the relationship with a database table, so that I can view this relationship from other non ejb applications.


Does anyone know the best approach to designing the 'user_role' Entity bean, should I just have the fk fields in the bean, or a User and a Role entity in there ?

many thanks
dan

[ryanramage]

I am having the same problem. Any solutions yet?

[foglesa]

In ejb 1.1 im not even sure I would use an entity bean for the user_role table. Of course if you are feeling adventurous you could look at jboss 3 alpha and use CMP2 with the relationships to do this much easier.

The overhead of an entity bean for a mapping table just doesnt make sense to me really in 1.1. Of course IMHO the or mapping in 1.1 was/is lacking anyway.

Al

[erik777]

I created a UserRole CMP. While I understand that 1.1 is lacking, I am counting on being able to upgrade it to 2.0 when JBoss 3 is ready. Believe me, I am waiting anxiously for 3.0.

Here's the bean:

[pre]
public class UserRoleBean extends BaseCMPBean {

// Private persistent properties
public Integer userId, roleId ;

/**
* Create an instance of a bean. Note that this method returns null because the real
* creation is managed by the EJB container.
*/
public Integer ejbCreate (Integer _userId, Integer _roleId )
{
setUserId(_userId);
setRoleId(_roleId);
return null;
}

public void ejbPostCreate(Integer _userId, Integer _roleId ) { }

public Integer getUserId() { return userId; }
public void setUserId(Integer _userId) { userId = _userId; }

public Integer getRoleId() { return roleId; }
public void setRoleId(Integer _roleId) { roleId = _roleId; }
}
[/pre]

[foglesa]

well it is out... :)

Here is the link.

http://prdownloads.sourceforge.net/jboss/jboss-3.0.0alpha.zip

Al

[kantek]

But if i don't want a EJB to make the binding between the 2 entities ? How i do this ?