Connecting to Oracle 12c

A couple of weeks ago, I installed Oracle 12c on my Debian amd64 system. It is pretty easy to do, all you have to do is create a few symlinks that fuck up your 32/64 lib dirs and hack the makefiles ... another story for another blog post.

Today, I would like to talk about Oracle's new CDB & PDB architecture.

SID is Viciously dead, they say, but instance name is not - this is crazy, I need the address of Larry's pharmacist, he must have good stuff.

So, I have an Oracle instance named myinstance, it contains the CDB and a few PDB's.


Now, I connect to Oracle using user sys, I immediately end up in the CDB. Usernames/schemas in a CDB require a silly prefix, WTF, this is not the case in a PDB and it gets worse ...

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
myinstance

So I change to a PDB:

SQL> alter session set container=MyPDB;

Session altered.

SQL>  select instance_name from v$instance;

INSTANCE_NAME
----------------
myinstance


Now, this makes sense, one instance with multiple DB's.

So, Oracle says we are on the same instance as the CDB. When I connect to the instance_name, I will always end up in the CDB .... to reach a PDB, I must connect with the service name, the service name is the name of the PDB, in my case MyPDB.


Now, why, why did they not deprecate connecting with instance_name ?


Always use the service name when you connect to Oracle, this is what they said in the ojdbc drivers for 10g, iirc.

  Connection conn = DriverManager.getConnection
     ("jdbc:oracle:thin:@//localhost:1521/MyPDB", "scott", "tiger");

However, they removed that recommendation in the  12c jdbc driver docs, do they need help or are they stupid ?