"i installed the ezoracle extension. Can anyone help in how to use it ? my goal is to display data in a page and these data should be retrieved from orcale db."
First, please read INSTALL file. It explains how to install the extension and make eZ publish use Oracle.
"what are the benefits of using ezoracle extension instead of using PHP to connect and fetch data from oracle db."
eZ publish does not use database directly. Instead, the interaction is done with ezdb library providing generic database access API. ezoracle contains a driver for ezdb that makes it possible to migrate an eZ publish site to Oracle. If your site is running on an other DBMS and you just need to execute a couple of Oracle queries, there's no need to use ezoracle.
If i just want to fetch some data from Oracle database for some pages on an ezpublish site. Do you advice to use ezoracle extension ? (it means i will keep mysql and connect to oracle to fetch these data only).
"ok, i won't use the ezoracle extension. Can i use ezDB class to connect to oracle DB ? if yes please could you explain how can i pass the parameters ?"
:-) Sure you can. But if you're using ezdb to connect to Oracle that implies using ezoracle as Oracle driver for ezdb.
Usage of ezdb over Oracle doesn't differ from using it over MySQL. Please see the INSTALL file.
the idea is that i will still use the mysql connection as a master connection, and for a specific case i want to use the oracle driver to connect to the oracle database to retreive some data for display.
how can i configure ezdb to use the ezoracle extension to do so?
the installation guide shows how to use the oracle connection as a master database connection and not as an oxiliary connection.
"the idea is that i will still use the mysql connection as a master connection, and for a specific case i want to use the oracle driver to connect to the oracle database to retreive some data for display." Yes, I understood.
"how can i configure ezdb to use the ezoracle extension to do so? the installation guide shows how to use the oracle connection as a master database connection and not as an oxiliary connection. "
You must pass some extra parameters to eZDB::instance() in this case. Example: