Archives For November 30, 1999

to be honest, I never was aware of this. there is a create schema command in oracle which can be used to populate a schema in a singe transaction:

create user u identified by u;
create user a identified by a;
grant create session, create table, create view to u;
alter user u quota 1m on users;
connect u/u
create schema authorization u
   create table t1 
      (a number, b varchar2(10))
   create view v1
      as select * from t1 where a = 1
   grant select on v1 to a;

this can be very handy if you want a script ( which creates some tables and views ) to be atomic. if there is an error in your create schema script like:

create schema authorization u
   create table t1
      (a number, b varchar2(10))
   create view v1
      as select **** from t1 where a = 1
   grant select on v1 to a;

… nothing will be created at all. you may fix the script and start over again ( without dropping anything as you would need to do it if you use single create commands ).

this is documented here.

here is a nice overview of the history of programming languages ( source: visual.ly ):

I always wonder that people don’t care about what the companies behind the popular search engines do with their data. but, at least for searching the web, there is an alternative which protects your privacy: startpage.com.

if you want to read a little summary, check this: aboutstartpage

and if you want to read even more, check this: First European Privacy Seal Awarded

plugins for most of the popular browser are available here.

there is a white paper which you definitely should read before you think about running an oracle database on zfs:

Configuring ZFS for an Oracle Database

fixing things afterwards might be tricky …

surprisingly less and less people seem to know this: the first six digits of a mac address identify the hardware vendor.

so, if you want to identify the vendor for a specific mac address just head over to IEEE and perform a search using the first six digits of the mac address.

or download the complete vendor list: oui download

while randomly browsing the oracle documentation I came across this sentence: “By definition, a schema name need not be just a simple SQL name. For example, “FIRST LAST” is a valid schema name.”

if this is true creating a database user consisting of two words must be possible:

create user "two words" identified by "blubb";
USER CREATED

works …

...ouch

if you want to know who is currently logged into the system and what they are doing, just type “w”:

/usr/bin/w
[root@xxxxxx ~]# w
 18:08:06 up  3:58,  5 users,  load average: 0.14, 0.05, 0.02
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     tty1     -                17:18   50:04   0.04s  0.04s -bash
root     pts/0    10.0.2.2         18:05    0.00s  0.05s  0.00s w
test1    pts/2    10.0.2.2         18:07    1.00s  0.03s  0.03s -bash
test2    pts/3    10.0.2.2         18:07    4.00s  0.06s  0.01s ping localhost
test3    pts/4    10.0.2.2         18:07   28.00s  0.09s  0.05s vim

… and to have some fun: if you want to send a message to e.g. the test1 user:

echo "i'll be watching you" >> /dev/pts/2

this will print the message on the test1 user’s screen:

[test1@xxxxxx ~]$ i'll be watching you

if you want to play around with freebsd here is a small intro:

  • download the cd iso from the website
  • create a new virtualbox machine all with the defaults
  • follow the freebsd installation process all with the defaults

if everything went fine you are presented with a shell after installation. to make it a bit more comfortable you may execute the commands below to create a user, configure the package repository and install kde4 ( if you prefer gnome or xfce check the documentation and adjust the commands below ):

bash
# in case you are behind a proxy
export http_proxy=[proxy]:[PORT]
# boostrap system for pkgng
cd /usr/ports/ports-mgmt/pkg
make
make install clean
# create the index
cd /usr/ports
make fetchindex
# set repository to use
export PACKAGESITE=http://ftp.freebsd.org/pub/FreeBSD/ports/amd64/packages-9-stable/Latest/
# install x11 and desktop environment
pkg_add -r xorg
pkg_add -r kde4
pkg_add -r virtuoso
echo "exec /usr/local/kde4/bin/startkde" > ~/.xinitrc
# enabling hal and dbus for keyboard and mice detection
echo "hald_enable=\"YES\" " >> /etc/rc.conf
echo "dbus_enable=\"YES\" " >> /etc/rc.conf
# enable kdm autostart
echo "kdm4_enable=\"YES\" " >> /etc/rc.conf
# misc ( virtual box addons for getting a higher resolution when running 
# as virtual box guest )
pkg_add -r virtualbox-ose-additions
echo "vboxguest_enable=\"YES\" " >> /etc/rc.conf
echo "vboxservice_enable=\"YES\" " >> /etc/rc.conf
# add sudo
pkg_add -r sudo
# mount /proc filesystem
mount -t procfs proc /proc
echo "proc            /proc           procfs  rw      0       0" >> /etc/fstab
# adding a user
mkdir -p /home/testuser
pw group add testuser
pw user add -n testuser -d /home/testuser -g testuser -s /usr/local/bin/bash
chown testuser:testuser /home/testuser
passwd testuser
echo "exec /usr/local/kde4/bin/startkde" > /home/testuser/.xinitrc
echo "%testuser ALL=(ALL) ALL" >> /usr/local/etc/sudoers
# install some software
pkg_add -r vpnc
pkg_add -r rdesktop
pkg_add -r KeePassX
pkg_add -r firefox
# get security patches and updates
freebsd-update fetch
freebsd-update install
# reboot and have fun
reboot

happy freebsding:

which way to choose ?
which way to choose ?

which way to choose ?