Connecting to remote database without using db links

Question

Referred Thread:
Re: Remote DB connection without DB link
In reference to the thread above, my question goes like this:
Let's say I want to run a query from a database and use data from another database. I have the user, password, SID and port number of the other database but do not want to create a separate connection using sqlplus or connect commands.
Something like this:
SQL> show user
USER is "A"
SQL> select a.col1, b.col2 from tab1 a, tab2@????? where <some condition>;
Can this connection be done on the fly ?? I agree that a DB link will do the trick, but let's say I am not supposed to create objects on the other database.

Answer 1

You need two sets of privs on the remote database to view data in that database schema:
- create session (the schema must allow client connections to create schema sessions)
- select on other schema tables whose contents to view
You need a single priv on the local database, to connect to that remote schema on the other database:
- create database link
You also need the following in order to create the db link:
- the remote schema name and password
- IP address or hostname of the remote db server
- the remote Listener's tcp endpoint port
- the name of the remote database (SID, instance or service name)
If you do not have these privs, you cannot use/access the remote database from the local database session via a database link.
Other alternative methods needs additional privileges and objects on both the remote and local database sides - and are more complex (e.g. using web services, using web-enabled procedures, etc).