Continuing the Oracle Cheat Sheet 🙂

1. Create an Oracle user

create user xxx identified by yyy;
grant connect, resource, unlimited tablespace to xxx [identified by yyy];
grant create session to xxx;

2. Extend tablespace

ALTER DATABASE
DATAFILE  'C:\ORACLEXE\ORADATA\XE\SYSTEM.DBF'
RESIZE 1000M;

link

3. Invoking UNIX commands from SQL*Plus

You can invoke a UNIX command from SQL*Plus by using “HOST COMMAND”:

host ls -la *.sql 

lists all SQL files in the current directory

4. ORA-28000: the account is locked

Ever got the account locked error?

alter user system account unlock

OTN Discussion Forums : SYSTEM Account LockedTimed.

5. If you get one of the following two Oracle errors:

ORA-12154: TNS:could not resolve the connect identifier specified
http://ora-12154.ora-code.com/

ora 06413 – connection not open
http://www.dba-oracle.com/t_ora_06413_connection_not_open.htm

…and you are using Navicat for Oracle, then check your Navicat installation path.
In my case, the error was caused by the parenthesis in the installation path: Program Files (x86). As soon as I reinstalled Navicat in Program Files, there were no more errors.

6. How to get the size of a blob field:

select
       length(mycol)
from
       mytable;

See more here