1. 15
PracNcal
PostgreSQL
Database
AdministraNon
Commands hTp://www.thegeekstuff.com/2009/04/15-‐pracNcal-‐postgresql...
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15
Prac(cal
PostgreSQL
Database
Administra(on
Commands
by
Ramesh
Natarajan
on
April
16,
2009
15 Like 7 Tweet 16
Earlier
we
discussed
about
how
to
install
PostgreSQL
database
on
Linux
from
source.
In
this
arNcle,
let
us
review
top
15
pracNcal
postgreSQL
DBA
command
examples.
If
you
are
a
mySQL
administrator,
check-‐out
our
15
examples
of
mysqladmin
command
arNcle
that
we
discussed
a
while
back.
1.
How
to
change
PostgreSQL
root
user
password
?
$ /usr/local/pgsql/bin/psql postgres postgres
Password: (oldpassword)
# ALTER USER postgres WITH PASSWORD 'tmppassword';
$ /usr/local/pgsql/bin/psql postgres postgres
Password: (tmppassword)
Changing
the
password
for
a
normal
postgres
user
is
similar
as
changing
the
password
of
the
root
user.
Root
user
can
change
the
password
of
any
user,
and
the
normal
users
can
only
change
their
passwords
as
Unix
way
of
doing.
# ALTER USER username WITH PASSWORD 'tmppassword';
2.
How
to
setup
PostgreSQL
SysV
startup
script?
$ su - root
# tar xvfz postgresql-8.3.7.tar.gz
# cd postgresql-8.3.7
# cp contrib/start-scripts/linux /etc/rc.d/init.d/postgresql
# chmod a+x /etc/rc.d/init.d/postgresql
3.
How
to
check
whether
PostgreSQL
server
is
up
and
running?
$ /etc/init.d/postgresql status
Password:
pg_ctl: server is running (PID: 6171)
/usr/local/pgsql/bin/postgres "-D" "/usr/local/pgsql/data"
[Note: The status above indicates the server is up and running]
1
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2. 15
PracNcal
PostgreSQL
Database
AdministraNon
Commands hTp://www.thegeekstuff.com/2009/04/15-‐pracNcal-‐postgresql...
$ /etc/init.d/postgresql status
Password:
pg_ctl: no server running
[Note: The status above indicates the server is down]
4.
How
to
start,
stop
and
restart
PostgreSQL
database?
# service postgresql stop
Stopping PostgreSQL: server stopped
ok
# service postgresql start
Starting PostgreSQL: ok
# service postgresql restart
Restarting PostgreSQL: server stopped
ok
5.
How
do
I
find
out
what
version
of
PostgreSQL
I
am
running?
$ /usr/local/pgsql/bin/psql test
Welcome to psql 8.3.7, the PostgreSQL interactive terminal.
Type: copyright for distribution terms
h for help with SQL commands
? for help with psql commands
g or terminate with semicolon to execute query
q to quit
test=# select version();
version
----------------------------------------------------------------------------------------------------
PostgreSQL 8.3.7 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20071124 (Red Hat 4.1.2-42)
(1 row)
test=#
5.
How
to
create
a
PostgreSQL
user
?
There
are
two
methods
in
which
you
can
create
user.
Method
1:
CreaNng
the
user
in
the
PSQL
prompt,
with
CREATE
USER
command.
# CREATE USER ramesh WITH password 'tmppassword';
CREATE ROLE
Method
2:
CreaNng
the
user
in
the
shell
prompt,
with
createuser
command.
$ /usr/local/pgsql/bin/createuser sathiya
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
CREATE ROLE
6.
How
to
create
a
PostgreSQL
Database
?
There
are
two
metods
in
which
you
can
create
two
databases.
Method
1:
CreaNng
the
database
in
the
PSQL
prompt,
with
createuser
command.
# CREATE DATABASE mydb WITH OWNER ramesh;
CREATE DATABASE
Method
2:
CreaNng
the
database
in
the
shell
prompt,
with
createdb
command.
$ /usr/local/pgsql/bin/createdb mydb -O ramesh
CREATE DATABASE
*
-‐O
owner
name
is
the
opNon
in
the
command
line.
2
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3. 15
PracNcal
PostgreSQL
Database
AdministraNon
Commands hTp://www.thegeekstuff.com/2009/04/15-‐pracNcal-‐postgresql...
7.
How
do
I
get
a
list
of
databases
in
a
Postgresql
database
?
# l [Note: This is backslash followed by lower-case L]
List of databases
Name | Owner | Encoding
----------+----------+----------
backup | postgres | UTF8
mydb | ramesh | UTF8
postgres | postgres | UTF8
template0 | postgres | UTF8
template1 | postgres | UTF8
8.
How
to
Delete/Drop
an
exis(ng
PostgreSQL
database
?
# l
List of databases
Name | Owner | Encoding
----------+----------+----------
backup | postgres | UTF8
mydb | ramesh | UTF8
postgres | postgres | UTF8
template0 | postgres | UTF8
template1 | postgres | UTF8
# DROP DATABASE mydb;
DROP DATABASE
9.
GeWng
help
on
postgreSQL
commands
?
will
show
PSQL
command
prompt
help.
h
CREATE
will
shows
help
about
all
the
commands
that
starts
with
CREATE,
when
you
want
something
specific
such
as
help
for
creaNng
index,
then
you
need
to
give
CREATE
INDEX.
# ?
# h CREATE
# h CREATE INDEX
10.
How
do
I
get
a
list
of
all
the
tables
in
a
Postgresql
database?
# d
On
an
empty
database,
you’ll
get
“No
relaNons
found.”
message
for
the
above
command.
11.
How
to
turn
on
(ming,
and
checking
how
much
(me
a
query
takes
to
execute
?
#
Nming
—
Ager
this
if
you
execute
a
query
it
will
show
how
much
Nme
it
took
for
doing
it.
# timing
Timing is on.
# SELECT * from pg_catalog.pg_attribute ;
Time: 9.583 ms
12.
How
To
Backup
and
Restore
PostgreSQL
Database
and
Table?
We
discussed
earlier
how
to
backup
and
restore
postgres
database
and
tables
using
pg_dump
and
psql
uNlity.
13.
How
to
see
the
list
of
available
func(ons
in
PostgreSQL
?
To
get
to
know
more
about
the
funcNons,
say
df+
# df
# df+
14.
How
to
edit
PostgreSQL
queries
in
your
favorite
editor
?
# e
3
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7 18
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12
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pm
4. 15
PracNcal
PostgreSQL
Database
AdministraNon
Commands hTp://www.thegeekstuff.com/2009/04/15-‐pracNcal-‐postgresql...
e
will
open
the
editor,
where
you
can
edit
the
queries
and
save
it.
By
doing
so
the
query
will
get
executed.
15.
Where
can
i
find
the
postgreSQL
history
file
?
Similar
to
the
Linux
~/.bash_history
file,
postgreSQL
stores
all
the
sql
command
that
was
executed
in
a
history
filed
called
~/.psql_history
as
shown
below.
$ cat ~/.psql_history
alter user postgres with password 'tmppassword';
h alter user
select version();
create user ramesh with password 'tmppassword';
timing
select * from pg_catalog.pg_attribute;
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{
6
comments…
read
them
below
or
add
one
}
1
sasikala
April
16,
2009
at
10:20
pm
It
is
very
simple
but
more
useful.
thanks.
2
mike
March
21,
2010
at
10:41
pm
very
useful
for
beginners
like
me.
Thanks.
3
karel
April
28,
2010
at
2:59
am
ager
using
d
i
get
list
of
the
tables
,and
highlighted
(END)
i
cannot
enter
any
text
or
command.
How
to
exit
the
descripNon
and
input
next
commands?
4
markitus82
May
18,
2010
at
10:03
am
thanks!
nice
guide!
4
of
7 18
Apr
12
7:18
pm
5. 15
PracNcal
PostgreSQL
Database
AdministraNon
Commands hTp://www.thegeekstuff.com/2009/04/15-‐pracNcal-‐postgresql...
5
NR
August
11,
2010
at
8:54
pm
Some
clarificaNons:
d
gaves
you
more
then
just
tables,
to
see
only
tables
use
dt.
To
see
views
use
dv,
to
see
a
table
or
any
other
object’s
descripNon
use
d
objectname.
You
can
use
?
to
see
a
list
of
commands
and
?
commandname
to
get
help
with
a
command.
The
same
way
you
can
use
h
to
see
a
list
of
SQL
commands
and
h
sqlcommand
to
get
help
with
a
SQL
command.
Be
aware
that
a
simple
create
database
command
will
create
a
database
with
default
parameters,
this
is
not
always
what
we
want
or
need.
Usually
it
is
ok
for
english
speakers
but
other
languages
migth
need
a
different
collaNng
order
or
even
encoding,
as
the
default
postgresql
installaNon
does
not
(or
did
not)
use
UTF-‐8.
To
change
this
and
other
parameters
in
a
safe
and
permanent
way
you
migth
need
to
create
a
all
new
database
cluster
as
some
parameters
cannot
be
changed
ager
database
creaNon
and
others
have
to
be
common
to
all
databases
(see
hTp://www.postgresql.org/docs/8.4
/interacNve/locale.html
for
postgreSQL
8.4).
Has
for
the
Karel’s
problem,
simply
use
‘q’
to
quit
the
viewing
and
came
back
to
the
prompt.
6
Anonymous
September
20,
2011
at
11:50
pm
this
is
very
useful
for
me
Leave
a
Comment
Name
E-‐mail
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me
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