Problem in connecting to database from webdynpro for java

Question

Hi
I have a problem in connecting to database from webdynpro application
I am using oracle 10 express edition as database and was able to connect to database from a java application.But  was unable to connect from a webdynpro for java.
<b>I guess webdynpro for java uses open sql instead of vendor sql(I looked in the visual admin ,DB is using open sql) so unable to connect to database.Am i right.?</b>
Do i need to make any settings in the visual admin to make it work?
How to solve this problem.Please give me pointers
Thanks
Bala

Answer 1

Hi,
For connecting to Oracle, either you can use the normal JDBC connectivty code directly which is given below :
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@Oracle_server_ip:Oracle port:SID of the Database","user_name","password");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("your query");
In case you want to fetch data through ejbs, these are the steps to be followed :
1) Open the J2EE perspective
2) Create an EJB Module project
3) Right click on ejbModule, create a new EJB (select your EJB type)
4) While creating the ejb itself, you can add business methods by clicking ‘Next’ in the UI. Another option is after creating the ejb, write the method in the bean, then select the method from ejb-jar.xml -> <bean name> ->method. Right click and select ‘propogate to local & remote’.
5) Double click on ejb-j2ee-engine.xml. select your bean and specify a Jndi name for eg: “MyJndi”.
6) Right click on the EJB project and add ‘classes12.zip’ file (provided by Oracle) to it’s build path. (under libraries tab). Also check the same file under ‘Order & Export’.
7) Create an Enterprise Application project.
8) Right click on the EJB module project and select add to EAR project, then select the created EAR project.
9) Right click on the EJB project, select ‘Build EJB Archive’
10) Right click on the EAR project, select ‘Build Application Archive’
11) Open the WebDynpro perspective, open a new project, right click on the project ->properties. Do the following configurations :-
• Java Build path - select the EJB project from ‘projects’ , check the selected project under ‘Order & Export’
• Project references – select the EAR project
• WebDynpro references – select ‘sharing references’ tab, click add & make an entry as : <vendor>/<EAR project name without .ear extension>
You can find the vendor name under ‘application-j2ee-engine.xml’ file of the EAR project. By default it is ‘sap.com’. So if my EAR project’s name is ABC, my entry would look like ‘sap.com/ABC’
12) Now the configurations are over and the EJB can be invoked by writing the client code inside the webdynpro component. Like:
InitialContext context = new InitialContext();
Object obj = context.lookup("MyJndi");
MyEJBHome home = MyEJBHome)PortableRemoteObject.narrow(obj,MyEJBHome.class);
MyEJB mybean = home.create();
int a = 0;
a= mybean.add(10,15);
wdContext.currentContextElement().setSum(a);
where ‘MyEJB’ is my EJB name and ‘MyJndi’ is my JNDI name
To connect to Oracle , you can write the usual Java code (given below) as a business methos of the ejb (similar to add() method in the example). And access it like mybean.<businessMethodName>().
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@Oracle_server_ip:Oracle port:SID of the Database","user_name","password");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("your query");
Extracted from Re: Webdynpro and Oracle
http://help.sap.com/saphelp_webas630/helpdata/en/b0/6e62f30cbe9e44977c78dbdc7a6b27/frameset.htm
May be of use to understand the VA Conf /people/varadharajan.krishnasamy/blog/2007/02/27/configuring-jdbc-connector-service-to-perform-database-lookups
Regards
Ayyapparaj