Hi all,
I've just started learning about EJBs, and now am at the stage of learning how to create, deploy and test a CMP Entity Bean.
Ran into a problem which I'm hoping someone can help out with.
I'm using SQL Server 2000 as my backend database, and have created a simple table called TEST with 2 fields, id and name. id is set as the primary key, and as an identity conlumn. What this means is that when we do inserts, we don't need to specify a value for the id column. SQL Servers automatically generates that value.
Here's my ejbCreate method in my bean class:
public Integer ejbCreate(String name) throws CreateException {
this.setName(name);
}
When I tried to run the create method from a web client, I got this error:
javax.ejb.CreateException: [EJB:010148]In EJB 'SampleEJB', the primary key field 'id' was not set during ejbCreate. All primary key fields must be initialized during ejbCreate. at weblogic.rmi.internal.ServerRequest.sendReceive(ServerRequest.java:186) at weblogic.rmi.cluster.ReplicaAwareRemoteRef.invoke(ReplicaAwareRemoteRef.java:284) at weblogic.rmi.cluster.ReplicaAwareRemoteRef.invoke(ReplicaAwareRemoteRef.java:244) at everbright.ejb.SampleEJB_uzc4wg_HomeImpl_813_WLStub.create(Unknown Source) at jsp_servlet.__index._jspService(__index.java:152) at weblogic.servlet.jsp.JspBase.service(JspBase.java:33) at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(ServletStubImpl.java:996) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:419) at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:315) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:6452) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:118) at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3661) at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2630) at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:219) at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:178)
So it seems like I can't leave the id field uninitialized in the ejbCreate method. However I don't know what to initialize it with either, because in order to know what value I need to initialize it to, I'll need to run a db query to retrieve the next primary key value for the id field. This doesn't sound very efficient to me.
I tried to initailize it to null, but that gave me a NullPointerException.
Why do we need to initialize the primary key field in ejbCreate? Should the container do the insert and then get it from the table accordingly?
Is there any other way I can get this set-up working?
Thanks!