You will need to re-write your question, because you are talking about 2 different things here.
Delphi is a programming language/tool, while Oracle 11g is a database management system. You can migrate from one development tool to another, and from one database to another but not from a IDE to a RDBMS. You can, though, write Delphi programms to connect to an Oracle database, and work with both simultaneously.
Could you please let us know what is excatly is what you need help with ?