How to query a distant database without using db link in pl/sql

Question

Hi
I have two different distantly located databases say d1,d2
There is a table dept which had deptno (primary key),department name as columns .
I need to query database d2 on the basis of the deptno present in database d1.
In database d2 , there are some tables which have columns as deptno.
I cannot use DB link .
Is there any other method that I can use from Pl/sql ?
Is it possible thru XML ?
PLs let me know in details .
regards
SHUBH

Answer 1

You need to have an Oracle Apache Server installed. It can be on any platform that has connectivity to the Oracle Server. Preferably on the same server as Oracle itself.
The Apache Server is installed in its ORACLE_HOME/Apache/Apache. It should have been configured by the installer. All you need to do is to create a DaD (Database Access Descriptor) for MOD_PLSQL. This is a custom Apache Module that provides direct access to PL/SQL via OCI. DaDs are defined in the ORACLE_HOME/Apache/modplsql/conf directory. There are README files, sample files and a dads.conf file in which you need to define a URL to assign as the service for your database, the Oracle username and password to use to logon, and the database connection details (e.g. TNS alias).
The Apache Server needs to be restarted for the changes to take effect (using either opmnctl or apachectl).
Let's say the URL path defined is /mydatabase. When Apache receives a URL that starts with /mydatabase, it passes it to MOD_PLSQL. MOD_PLSQL looks in the dads.conf for the database to connect to. The rest of the URL contains the PL/SQL package or function to call, e.g.
/mydocuments/scott.p123.procABC&emp_id=123
Where procedure procABC is called in packahe p123 in the Scott Schema. The variable EMP_ID is passed with value 123. Thus the procABC definition will look as follows in the package:
procedure procABC( emp_id number ) is
begin
  .. code..
end.;This proc can write HTML data - i.e. dynamically create a HTML response page. Or it can create an image or any other Mime type that the browser can handle.
Oracle provides a bunch of PL/SQL packages for that. E.g. HTP and OWA packages.
This in a nutshell is how MOD_PLSQL is used to allow a web browser URL to be passed directly to a PL/SQL procedure.
The details are under Oracle Application Server PL/SQL (http://download-west.oracle.com/docs/cd/B14099_12/web.htm). Two manuals are applicable:
* mod_plsql User's Guide
* Web Toolkit Reference
It is not complex to use. In fact, the easiest to get all this going is to install HTMLDB 2. Download the Oracle 10G Companion CD for your platform (even if you're running 9.2). Install HTMLDB (this will be in a seperate ORACLE_HOME and will not touch your existing Oracle installation). This will install the latest Apache and MOD_PLSQL software from Oracle. Also HTMLDB is built entirely on MOD_PLSQL and with PL/SQL procedures - and serves as Microsof Access type web interface for developing and deploying web applications on Oracle using PL/SQL. Very powerful and flexible and very easy to use.