Entity EJBs

Hello!!
My application works with tables in a Oracle database but I have several Entity EJB too .. is it absolutely necessary to create the tables that are used by the Entity EJBs in a data dictionary project?
I hope anybody help me.
Thanks

Hi,
no, using Data Dictionary is necessary only if you want to use OpenSQL to access the database. In your case you can use EJBs with Vendor of Native SQL DB access. For more info on the persistency layers that are available on the Web AS Java, see <a href="http://help.sap.com/saphelp_nw04/helpdata/en/61/fdbc3d16f39e33e10000000a11405a/frameset.htm">this page</a>.

Similar Messages

How to use the same Entity EJB to access the same table in 2 syb databases

We are trying to convert an application to J2EE. We have the following
concern. The application requires the use of 10 sybase databases with
identical tables. One database per branch. We would like to be able to use the same set of entity EJBs to access all databases.
One solution we can think of is to use bmp entity beans and have a dispatcher session bean pass the database that the entity bean has to connect to.
Would it work?
Is there a more elegant way to do this?

I don't know if there is a more elegant way to do it, but that will work. I have a similar scenario, one database per customer. You'll have to use BMP and get your connections based on the branch.
Each one of my DAO methods requires that a customer ID be passed in for each method. The customer ID is part of the primary key for each entity bean; therefore, if I need to find a deposit (entity) for a customer, I pass the customer ID and deposit ID to my session facade, create the PK using these, do a findByPrimaryKey, etc. In the ejbLoad, I use the customer ID and the deposit ID to pass into the DAO. There, another class (ConnectionFactory) returns a proper connection based on the customer ID passed, which I use to do my queries.
Paul

Oracle Dabase Schema with OC4J CMP Entity EJB

I have tables in a schema called vsxlib. My Entity EJBs that map to SQL SERVER tables (no schema) work perfectly. My Entity CMP EJBs that connect need to connect to the vsxlib schema only partially work.
The findAll method works. When I add a where clause, I get no results back.
When I try a findByPrimaryKey, I get a ObjectNotFoundException.
Does OC4J version 9.0.3 support database schemas? There were examples posted at http://otn.oracle.com/sample_code/tech/java/j2ee/javacookbook/transactionsample/readme.html#descfiles say that they have an Entity bean working within a db schema.
Could it be permission related????
I even tried creating a synonym pointing to the table within the vsxlib schema.. No Luck.
I had this same problem with JBoss3.2 and found out that they did not support db schemas. That is why I was wanting to switch to OC4J because I thought for sure, being an oracle product that it would support db schemas.
Any help is greatly appreciated.

Hi Alex,
I think you may be misunderstanding the meaning of 'database schemas'. For your information, in the Oracle database, a schema is the same as a database user. For example all the database tables belonging to user SCOTT (TIGER) are said to be in the SCOTT schema.
OC4J uses the term 'database schema' differently. Here it refers to the mapping of database datatypes to java classes. Look at the "j2ee/home/config/database-schemas" subdirectoryof the OC4J installation for more details. The "data-sources.xml" file has a 'schema' tag (not sure if that's the correct name) which points OC4J to the datatype mapping XML file -- usually one of those that come with the distribution. However, I use OC4J stand-alone version and I don't need to worry about the mappings at all -- OC4J already knows the mappings for an Oracle database (I assume).
In order to access a particular Oracle schema, I merely have to log in to the database as the appropriate user. So, using the previous example, if I configure the "data-sources.xml" file to use 'scott' as the database login, then OC4J can access the SCOTT schema. You can find more details about Oracle's use of the term 'schema' in the Oracle documentation, which is available from:
http://tahiti.oracle.com
Hope this has answered your question.
Good Luck,
Avi.

Oracle sequence problem in CMP Entity EJB

I have a problem with Oracle sequence when I am using from the CMP entity EJB in WebLogic
6.1:
The problem is when the WebLogic server starts it acquires the correct sequence number
from Oracle, but during the runtime, when I open a new sqlplus window and increment
the sequence number, the container is not picking up from the new incremented value
instead it is still continuining by incrementing the old sequence number it has acquired
when it fetched from Oracle last time.
The sequence increment and key-cache-size in weblogic-cmp-rdbms-jar.xml are exactly
same
Any help would be greatly appreciated.

Change the key-cache-size to 1 in weblogic-cmp-rdbms-jar.xml and then try
your experiment again.
-- Anand
"Satya" <[email protected]> wrote in message
news:3d06274c$[email protected]..
>
I have a problem with Oracle sequence when I am using from the CMP entityEJB in WebLogic
6.1:
The problem is when the WebLogic server starts it acquires the correctsequence number
from Oracle, but during the runtime, when I open a new sqlplus window andincrement
the sequence number, the container is not picking up from the newincremented value
instead it is still continuining by incrementing the old sequence numberit has acquired
when it fetched from Oracle last time.
The sequence increment and key-cache-size in weblogic-cmp-rdbms-jar.xmlare exactly
same
Any help would be greatly appreciated.

Database Views with Entity EJBs

Is it possible to use Weblogic Workshop to create a CMP entity EJB on an Oracle database view for a Weblogic 8.1 server?
Is there special configuration I need to do for either the Oracle or Weblogic side to accomplish this?
Thanks.
Tania

I can manually create the EJB, an it builds just
fine, but when I go to deploy it, I get the following
error:
[EJB:011076]Unable to deploy the EJB
'AssortmentMerchandise' because the databas
e table 'K_BA01.BAV_ASRT_CLUSTR_DAT' is not
accessible. Please ensure that this
table exists and is accessible.
The view is on the same datasource that I have
successfully created all of my other entity EJBs
(from tables).
I can select data from the view using JDBC and the
same datasource that I am trying to associate the EJB
to.
Any ideas what might be wrong with my view?Are you using synonyms or aliases? I would double check those...
Log in using same username and password as weblogic and try a simple query:
select * from K_BA01.BAV_ASRT_CLUSTR_DAT

How to set the isolation level on Entity EJBs

I am using 10.1.3.3 of the OC4J app server.
I am creating an application that uses EJB 2.1.
I am trying to set the isolation levels on the EJBs to either serializable or repeatable read.
When i deploy the EAR file from the OC4J admin console, i can set the isolation level property on the EJB's however when i inspect the orion-ejb-jar.xml file I do not see the isolation level being set. Furthermore, i tried to manually change the isolation setting by editing the orion-ejb-jar.xml and adding the isolation="serialiable" attribute on the entity bean descriptor. I then stopped and restarted the server. I noticed that my change was no longer in the file.
Can someone please let me know how to solve this problem and set the isolation level on Entity EJBs . Thanks

I find it at ejb.pdf from BEA.
          The transaction-isolation stanza can contain the elements shown here:
          <transaction-isolation>
          <isolation-level>Serializable</isolation-level>
          <method>
          <description>...</description>
          <ejb-name>...</ejb-name>
          <method-intf>...</method-intf>
          <method-name>...</method-name>
          <method-params>...</method-params>
          </method>
          </transaction-isolation>
          "Hyun Min" <[email protected]> wrote in message
          news:3c4e7a83$[email protected]..
          > Hi!
          >
          > I have a question.
          > How to set the transaction isolation level using CMT in descriptor?
          >
          > The Isolation level not supported in CMT?
          >
          > Thanks.
          > Hyun Min
          >
          >

Mapping of an entity EJB to multiple database tables using CMP?

Can one entity EJB have attributes split between (mapped to) multiple databse tables?
Would CMR work properly between two such entity EJBs (both mapped to multiple database
tables).

Hi Milos.
Can one entity EJB have attributes split between (mapped to) >>multiple databasetables?
A CMP Entity should be always mapped a record in a single DB table.
Thanks.
Ji Zhang
Developer Relations Engineer
BEA Support

Bmp entity ejb transactions, using DAO objects

hi all,
i'm new to entity ejb's... i'm using the j2ee reference implementation (1.3.1) with the cloudscape db to test my code.
i can't seem to get my ejbCreate method to work. i'm using a DAO object to encapsulate all my database code, and simply call dao.insert(...) in my ejbCreate method.
i tested the dao object, and it works fine when it's invoked straight. but when i try to invoke under the ejb container i run into problems:
i deploy the bean with container managed transactions:
(1) with the 'required' attribute:
I get a javax.transaction.RollbackException nested inside another RollbackException, nested inside a RemoteException, nested inside another RemoteException. The final RollbackException says <<no stack trace available>>...
So I've got no clue what's causing it...
(2) with the 'never' attribute:
I get a NullPointerException nested inside another NullPointerException, nested inside a RemoteException, nested inside another RemoteException. The final NullPointerException says <<no stack trace available>>...
So I've got no clue what's causing it...
I'm assuming something messed up with my deployment -- but I've checked it against all the examples I can find -- seems to be correct. Would the encapsulated Data Access code cause a problem? Some other config problem?
Thanks in advance for any help!!

i'm using the cloudscape db that's already configured with the server. i believe the datasource is correctly configured, as i am able to successfully invoke the dao methods straight -- the problem occurs when I try to do it via the entity bean that uses the dao object.
here's my server startup messages:
Binding DataSource, name = jdbc/Cloudscape, url = jdbc:cloudscape:rmi:CloudscapeDB;create=
true
Binding DataSource, name = jdbc/DB1, url = jdbc:cloudscape:rmi:CloudscapeDB;create=true
Binding DataSource, name = jdbc/EstoreDB, url = jdbc:cloudscape:rmi:CloudscapeDB;create=tr
ue
Binding DataSource, name = jdbc/InventoryDB, url = jdbc:cloudscape:rmi:CloudscapeDB;create
=true
Binding DataSource, name = jdbc/DB2, url = jdbc:cloudscape:rmi:CloudscapeDB;create=true
Binding DataSource, name = jdbc/XACloudscape, url = jdbc/XACloudscape__xa
Binding DataSource, name = jdbc/XACloudscape__xa, dataSource = COM.cloudscape.core.RemoteX

Deployment error: The Entity EJB requires the table: to be accessible

Hello
When I deploy my EJBs, WEBLogic throws an exception:
Unable to deploy EJB: OrderBean from ejb-jar-ic.jar:
The Entity EJB requires the table: Order to be accessible. Please ensure that th
is table exists and is accessible.
I use built in Cloudscape database.
And I have those lines in descriptor:
<weblogic-rdbms-bean>
<ejb-name>OrderBean</ejb-name>
<data-source-name>ejbDS</data-source-name>
<table-name>Order</table-name>
<field-map>
<cmp-field>totalAmount</cmp-field>
<dbms-column>totalAmount</dbms-column>
</field-map>
<field-map>
<cmp-field>time</cmp-field>
<dbms-column>ordertime</dbms-column>
</field-map>
<field-map>
<cmp-field>orderID</cmp-field>
<dbms-column>orderID</dbms-column>
</field-map>
</weblogic-rdbms-bean>
<create-default-dbms-tables>True</create-default-dbms-tables>
thanx in advance
Maris

Hi Maris,
I see that you have create-default-dbms-tables set to true so WLS should be creating
the database table for your EJB. If you can give me some more information, I'll be
able to help you further. What version of WLS + service pack are you using? Also,
is this a 1.1 bean or 2.0? Lastly, what are the types of the CMP fields in your
bean?
As a work-around, you can try creating the database table yourself before deploying
the bean. This should resolve the deployment problem.
- Matt
Maris wrote:
Hello
When I deploy my EJBs, WEBLogic throws an exception:
Unable to deploy EJB: OrderBean from ejb-jar-ic.jar:
The Entity EJB requires the table: Order to be accessible. Please ensure that th
is table exists and is accessible.
I use built in Cloudscape database.
And I have those lines in descriptor:
<weblogic-rdbms-bean>
<ejb-name>OrderBean</ejb-name>
<data-source-name>ejbDS</data-source-name>
<table-name>Order</table-name>
<field-map>
<cmp-field>totalAmount</cmp-field>
<dbms-column>totalAmount</dbms-column>
</field-map>
<field-map>
<cmp-field>time</cmp-field>
<dbms-column>ordertime</dbms-column>
</field-map>
<field-map>
<cmp-field>orderID</cmp-field>
<dbms-column>orderID</dbms-column>
</field-map>
</weblogic-rdbms-bean>
<create-default-dbms-tables>True</create-default-dbms-tables>
thanx in advance
Maris

Deploying CMP Entity EJB: NullPointerException

Hi,
I have built a very simple CMP Entity EJB, when deploying it to Oracle8i 8.1.7, it fails and return this error:
Processing container managed persistence bean...java.lang.NullPointerException
java.lang.Class java.lang.Class.forName0(java.lang.String, boolean, java.lang.ClassLoader)
java.lang.Class java.lang.Class.forName(java.lang.String)
void oracle.aurora.ejb.deployment.GenerateEjb.cmpDeploy(oracle.aurora.ejb.dd.OracleEntityDescriptor)
void oracle.aurora.ejb.deployment.GenerateEjb.invoke()
void oracle.aurora.server.tools.sess_iiop.ToolImpl.invoke(java.lang.String[], java.io.InputStream, java.io.PrintStream, java.io.PrintStream)
void oracle.aurora.ejb.deployment.GenerateEjb.main(java.lang.String[])
Can anyone help????
Patrick.
null

I have the same problem with JDeveloper 3.2.3 and 8.1.7.2
Here is the error:
*** Executing deployment profile E:\Xaris\JDeveloper\General\EJBs\EmpCmp\EmpCmp.prf ***
*** Generating archive file E:\Xaris\JDeveloper\General\EJBs\EmpCmp\empcmp.jar ***
Compiling the project...done
Validating the profile...done
Initializing deployment...done
Scanning project files...done
Generating classpath dependencies...done
Generating archive entries table...done
*** Archive generation completed ***
*** Deploying the EJB to 8i JVM ***
EJB deployment argument list:
"E:\Program Files\Oracle\JDeveloper 3.2.3\java1.2\jre\bin\javaw"
"-DPATH=E:\Program Files\Oracle\JDeveloper 3.2.3\bin;E:\Program Files\Oracle\JDeveloper 3.2.3\java1.2\bin"
-classpath
"E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\aurora_client.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\lib\javax-ssl-1_2.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\jasper.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\vbjorb.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\vbjapp.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\vbjtools.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\vbj30ssl.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\aurora.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\sqlj\lib\translator.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\sqlj\lib\runtime.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\aurora\lib\mts.jar;E:\Xaris\JDeveloper\General\EJBs\EmpCmp\classes;E:\Program Files\Oracle\JDeveloper 3.2.3\lib\jdev-rt.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\jdbc\lib\oracle8.1.7\classes12.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\lib\connectionmanager.zip;E:\Program Files\Oracle\JDeveloper 3.2.3\lib\javax_ejb.zip;C:\Program Fil
s\JavaSoft\JRE\1.3.1\lib\i18n.jar;C:\Program Files\JavaSoft\JRE\1.3.1\lib\jaws.jar;C:\Program Files\JavaSoft\JRE\1.3.1\lib\rt.jar;C:\Program Files\JavaSoft\JRE\1.3.1\lib\sunrsasign.jar;E:\Program Files\Oracle\JDeveloper 3.2.3\lib\xmlparserv2.jar"
oracle.aurora.ejb.deployment.GenerateEjb
-u
harris
-p
harris
-s
sess_iiop://192.168.10.218:2481:WORK
-republish
-keep
-temp
TEMP
-descriptor
"E:\Xaris\JDeveloper\General\EJBs\EmpCmp\EmpCmp.xml"
-oracledescriptor
E:\Xaris\JDeveloper\General\EJBs\EmpCmp\EmpCmp_oracle.xml
-generated
"E:\Xaris\JDeveloper\General\EJBs\EmpCmp\EmpCmpClient.jar"
"E:\Xaris\JDeveloper\General\EJBs\EmpCmp\empcmp.jar"
Reading Deployment Descriptor...done
Verifying Deployment Descriptor...done
Gathering users...done
Processing container managed persistence bean...java.lang.NullPointerException
     java.lang.Class java.lang.Class.forName0(java.lang.String, boolean, java.lang.ClassLoader)
     java.lang.Class java.lang.Class.forName(java.lang.String)
     void oracle.aurora.ejb.deployment.GenerateEjb.cmpDeploy(oracle.aurora.ejb.dd.OracleEntityDescriptor)
     void oracle.aurora.ejb.deployment.GenerateEjb.invoke()
     void oracle.aurora.server.tools.sess_iiop.ToolImpl.invoke(java.lang.String[], java.io.InputStream, java.io.PrintStream, java.io.PrintStream)
     void oracle.aurora.ejb.deployment.GenerateEjb.main(java.lang.String[])
null
*** Errors occurred while deploying the EJB to 8i JVM ***
*** Deployment completed ***
Does anyone know what is the problem?

Session EJB vs ENtity EJB

Why/When would you use Session EJB instead of Entity EJB to access Database values

You might use a Session Bean to access the database when you didn't want the overhead of Entity Beans or if the data you were retrieving didn't relate to the entity structure easily.
Have a look at the Fast Lane Reader pattern in the J2EE Design Patterns section to get more information about an example. Here the data is only being read and presented to the user so support for updating the values, security and concurrency isn't needed and is purely overhead.
Hope this helps.

Remove methods in Entity EJBs

Hi,
I have a entity EJB with following methods:
findByPrimaryKey(PK)
create(PK)
get and set methods
I wanna add a remove method which will take the PK and delete the record for
me.
Please tell me the changes I have to incorporate. and How do i do it. I am using VA 3.5 and WAS 3.5
Thanx & Regards
Ravi Mittal

hi,
after adding access bean & generating deployed code you have to add remove method in Access Bean by yourself. remove(object) is in EJBhome interface.
you have to pass object of key class. so add empty remove() in acees bean. instantiate ur key class there & call remove(keclassobject) method. I think it will help you.
-priya

How a stateful session ejb invoke an entity ejb

i have write a stateful session ejb and an entity ejb
i want to invoke the method of the entity ejb in the session ejb.
Do they should in the save package,and archive to a jar package?
Thanks:)

the choice is yours
It not necessary that they shoule be in the same package
Work both ways
You make a call to it in the same way as you call it from a client
i.e. to say that an EJB can invoke another in the same way as a client invoke it...make the home object et.al
Regards
Sanjay

HELP - ERROR INVOKING ENTITY EJB METHOD

Hi,
I keep getting a java.rmi.NoSuchObject exception when using my entity ejb, but cannot see why, as I already have the ejb in a collection... code & stack trace below: Any one know what is causing this ??
java.rmi.NoSuchObjectException: com.syntegra.cec.insurance.entity.AATreportPK@7a6c34
java.rmi.NoSuchObjectException: com.syntegra.cec.insurance.entity.AATreportPK@7a6c34 at AATreport_EntityBeanWrapper14.getPayment_reference(AATreport_EntityBeanWrapper14.java:1881) at com.syntegra.cec.insurance.dtofactory.RecordsDTOFactoryBean.fetchAAT(RecordsDTOFactoryBean.java:151) at com.syntegra.cec.insurance.dtofactory.RecordsDTOFactoryBean.fetchRecords(RecordsDTOFactoryBean.java:62) at RecordsDTOFactory_StatelessSessionBeanWrapper49.fetchRecords(RecordsDTOFactory_StatelessSessionBeanWrapper49.java:108)
HashMap records = new HashMap();
Collection theEJBs = null;
int counter = 0;
//Find the beans
AATreportHome home = (AATreportHome)lookUpHome
(com.syntegra.cec.insurance.entity.AATreportHome.class,
"AATreport");
theEJBs = home.findByStatus(type);
//Populate the DTO's
if(theEJBs != null)
Iterator it = theEJBs.iterator();
while(it.hasNext())
AATreport theEJB = (AATreport)it.next();
AATreportDTO theDTO = new AATreportDTO
----- This is where the error comes from --
---Line 151 ---(theEJB.getPayment_reference(),
theEJB.getTenant_ref_no(),
theEJB.getInsurance_no(),
theEJB.getName(),
theEJB.getAddress_line_1(),
theEJB.getPremium(),
getDateAsString(theEJB.getAction_date()));
records.put(new Integer(counter), theDTO);
counter++;

Greetings,
Hi,
I am trying to access a bean from a JSP and have the
foll. code piece:
<%
String op="";
try {
// Contact the AccountBean container (the "AccountHome") through JNDI.
Context ctx = getInitialContext();
out.println("initial context got !!");
DemoHome home = (DemoHome) ctx.lookup("demo.DemoHome");
out.println("home got !!");Though it doesn't seem to be the problem in this case, good EJB coding practices dictate that your code should be narrowing the home reference before calling any of it's methods (i.e. create(...) )... WebLogic may allow handling of its protocol objects in their native state, but other vendors do not... your application is not portable without narrowing.
It gives an error on trying to access the method "demoSelect".
e.printStackTrace gives the output:
java.lang.RuntimeException: javax.ejb.EJBContext.getEnvironment is deprecated inThe error is not in your JSP, but in the bean... it seems your bean is attempting to acquire its "environment properties" in the pre-1.1 style, when...
EJB 1.1. EJB 1.1 compliant containers are not required to implement this
method. Use java:comp/env instead. ...instead, it should be looking them up in its JNDI namespace.
What is wrong???
pls help! Regards,
Tony "Vee Schade" Cook

Entity EJB Relationships Architectural Question

I need to create a hierarchy of simple objects. I will call my object
"Part" for simplicity. I have two Oracle tables to maintain my Part
hierarchy. The first table contains the detail for the part: number and
name. The second table maintains the relationship: parent_number and
child_number. I built Entity EJBs with CMP for both tables, but I don't
know if that is the "best practices" approach. If it is, how do I define
the relationships (EJB 2.0)? If it is not, how would you build it?
Thanks for helping me out,
Thomas A. Valletta

Thanks Slava,
You deserve more than a free trip to a conference for the time and effort
that you put into this board. I think you should be able to write this off
as a charitable contribution on your taxes. If you need someone to sign the
receipt, just let me know.
Anyway, back to my hierarchy issue(s). I found some information that
weblogic will set-up this kind of many-to-many relationship for you if you
set it up correctly in the weblogic-cmp-rdbms-jar.xml and the ejb-jar.xml.
So I went through the DTDs, but despite the examples the help is extremely
vague. Has anyone done this? Could anyone recommend where I could find
something more on the topic (books, magazine articles, online documentation,
code, etc)?
Thanks again,
Thomas A. Valletta
"Slava Imeshev" <[email protected]> wrote in message
news:3ec552f9$[email protected]..
Hi Thomas,
"Thomas A. Valletta" <[email protected]> wrote in message
news:[email protected]..
I need to create a hierarchy of simple objects. I will call my object
"Part" for simplicity. I have two Oracle tables to maintain my Part
hierarchy. The first table contains the detail for the part: number and
name. The second table maintains the relationship: parent_number and
child_number. I built Entity EJBs with CMP for both tables, but I don't
know if that is the "best practices" approach. If it is, how do I
define
the relationships (EJB 2.0)? If it is not, how would you build it?The best approach is the one that works for you. If the
combination of two beans works, leave it as is and
go ahead with next tasks.
Regards,
Slava Imeshev

Entity EJBs

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