Friday, June 08, 2012

Quiz: Mystery of Create Table Statement

Happy Friday! I thought I would jumpstart your creative juices with this little, really simple quiz. While it's trivial, it may not be that obvious to many. See if you can catch it. Time yourself exactly 1 minute to get the answer. Tweet answer to me @arupnanda

Here it goes. Database is Tool is SQL*Plus.

The user ARUP owns a procedure that accepts an input string and executes it. Here is the procedure.

create or replace procedure manipulate_arup_schema
        p_input_string  varchar2
        execute immediate p_input_string;

The user ARUP have granted EXECUTE privileges on this to user SCOTT. The idea is simple: SCOTT can create and drop tables and other objects in ARUP's schema without requiring the dangerous create any table system privilege.

With this, SCOTT tries to create a table in the ARUP schema:

SQL> exec arup.manipulate_arup_schema ('create table abc (col1 number)')

PL/SQL procedure successfully completed.
The table creation was successul. Now SCOTT tries to create the table in a slightly different manner:

SQL> exec arup.manipulate_arup_schema ('create table abc1 as select * from dual');
It fails with an error:

BEGIN bus_schema.manipulate_bus_schema ('create table abc as select * from dual'); END;

ERROR at line 1:
ORA-01536: space quota exceeded for tablespace 'USERS'
ORA-06512: at line 1

Huh? After checking you did confirm that the user indeed doesn't have the quota on tablespace USERS, so the error is genuine; but how did the first table creation command go through successfully?

Tweet me the answer @arupnanda. Aren't on Twitter? Just post the answer here as a comment. I will post the answer right here in the evening. Let's see who posts the first answer. It shouldn't take more than 5 minutes to get the answer.

Have fun.

Update at the end of the Day. Here is the answer:

Thursday, June 07, 2012

What to Learn from LinkedIn Password Hack as an Oracle DBA

One of the major news today was the hacking and resultant publishing of passwords in LinkedIn. Didn't hear about it? Well, read it here. In summary, someone smart but with head screwed a little askew decided to pull passwords from LinkedIn account using a little known flaw in the LinkedIn iOS app. LinkedIn later confirmed that leak and asked users to change the password. This created a major ripple effect all over the world. The news competed for attention with others such as Spain's economic reforms; but in the end it managed to rise to the top since many professionals and executives are members of the LinkedIn site and were affected.

Well, what is that to do with being an Oracle DBA - you may ask. Fair question. You see, there is a very important lesson to be learned here from this incident - a lesson commonly ignored by many DBAs, developers, architects and pretty much all users of an Oracle database. Let's see what that is.