Facts about the Enterprise JavaBeans (EJB) relation assembly setting, "Cascade delete" for container-managed persistence (CMP) and container-managed relationship (CRM)
 Technote (troubleshooting)
 
Problem(Abstract)
Can you set up a CMP enterprise bean with both the Enterprise JavaBeans relation "Cascade delete" assembly setting and the Oracle database "Cascade delete" Foreign Key function?
 
Resolving the problem
In the IBM WebSphere Application Server V5.0 Information Center, the EJB relation assembly settings describe the Enterprise JavaBeans relation as a relationship between two entity beans with container-managed persistence (CMP).

Cascade delete is described as within a particular relationship, and it specifies that the lifespan of one or more entity beans is dependent upon the lifespan of another entity bean. Cascade delete can be specified only for an Enterprise JavaBeans relationship role contained in an Enterprise JavaBeans relation in which the other Enterprise JavaBeans relationship role specifies a multiplicity. Multiplicity can be thought of as specifying the multiplicity of the role that participates in a relation.

In general, for an enterprise bean, if it is designed to be CMP or CRM, the application should allow the Persistence Manager to handle all of the operations. If there is a "third-person" intervention on the Container Managed xxx operation, there might be undesirable side-effects. For example, depending on who (Persistence Manager or Database Manager) removes the relationship first, the second component coming in might or might not handle the removal correctly (For example, exception handling).

The Persistence Manager usually ignores exceptions if the relation does not exist. However, it is not guaranteed from the Database perspective. The bottom line is that if the application uses Container Managed semantics, then the container and the Persistence Manager should be allowed to perform their job. External interference is not recommended.
 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > EJB Container
Operating system(s): Windows
Software version: 5.0.2.4
Software edition:
Reference #: 1163248
IBM Group: Software Group
Modified date: Sep 10, 2004