[PostgreSQL] Take backup of the individual table in postgres

By Administrator on 8:13 PM in PostgreSQL, psql

pg_dump -t <table-name> <database-name> > /tmp/file_name.dump

[Ruby On Rails] Get the variable type in ruby on rails

By Administrator on 9:14 PM in is_a, ruby, ruby on rails, rubyonrails

is_a()

addr = Array.new
addr.is_a?Array #returns true

[Ruby on Rails] Get the last date of the month in ruby on rails

By Administrator on 1:25 AM in end_of_month, rails, ruby, ruby on rails, rubyonrails

dd = 11 # which means tha month november
dd_end_txt = `date -d "#{mm}/1 + 1 month - 1day"`
# which returns "Sat Nov 30 00:00:00 IST 2013\n"
dummy = dd_end_txt.split(" ")
dd_end = dummy[2] if(dummy != nil)

# Result is 30

[Ruby on Rails]: remove empty array elements in ruby on rails

By Administrator on 11:18 PM in rails, ruby on rails, rubyonrails

Method 1
arr = ["1","2",""]
arr.delete("")

Method 2
arr.reject! { |e| e.empty? }

[Javascript]: Unload Event upon closing the page

By Administrator on 12:24 AM in javascript, onunload

[PSQL]: Take Database Dump/Backup

By Administrator on 5:36 AM in PostgreSQL, psql

pg_dump dbname > outfile

Random Number Generation

By Administrator on 3:50 AM in javascript, ruby, ruby on rails, rubyonrails

Ruby
chars = ("a".."z").to_a + ("1".."100").to_a
random1 = Array.new(10, '').collect{chars[rand(chars.size)]}.join

Javascript:
var rand = Math.random() * 1000000000 * Math.random();
or
var rand = Math.random() * 1000000000

This is another efficient way to generate random number

[RUBY]: Duplicate the database record to the same table

By Administrator on 2:30 AM in ruby, ruby on rails

Example:
@user = Users.find(params[:id])
@user_new = User.new(@user.attributes)
@user.created_at = Time.now #update the field in the new record
@user_new.save

Convert the text or alphanumeric string to Integer value

By Administrator on 9:32 PM in javascript, ruby

Javascript
var str = "055"
str = str.parseInt;
alert(str); // this alerts the integer value 55

SVN: Get the latest revison number using SVN DIFF

By Administrator on 11:44 PM in linux, svn

svn diff <file-name>
--- app/asdf.html (revision 4564)
+++ app/asdf.html (working copy)

< will list the difference between the working copy and latest revision>

LINUX: Search matching files using grep command

By Administrator on 10:25 PM in grep, linux

grep -rl "date_functions()" app/

Output Controls
-R, -r, --recursive equivalent to --directories=recurse
-l, --files-with-matches print only names of FILEs containing matches

RUBY: Simple code to display N number of string or spaces in ruby on rails

By Administrator on 12:32 AM in ruby, rubyonrails

<%= ' ' * 5 %>

Outputs:

     

RUBY: Numeric validation using regular expression

By Administrator on 2:16 AM in regular expression, ruby, rubyonrails

numeric_var =~ /^[-+]?[0-9]*\.?[0-9]+$/

RUBY: Date and Time functions in ruby on rails

By Administrator on 3:00 AM in date, rails, ruby, rubyonrails

To get the current time:
time = Time.now

To get the current year:
year = Time.now.Year

RUBY: Search past N months record in ruby on rails

By Administrator on 11:36 PM in rails, ruby, rubyonrails

Search past 3 months records:
Event.find(:all, :conditions => ["created_at > ? ",Time.now - 3.month])

LINUX: Shortkut keys to use Konsole

By Administrator on 11:27 AM in konsole, linux, shortcuts

Activate Menu-> Ctrl+Shift+F10
Add Bookmark -> Ctrl_Shift+B
Clear Scrollbak and Reset -> Ctrl+Shift+X
Close Active Tab -> Ctrl+Shift+S
Close Other Tabs -> Ctrl+Shift+O
Close Current Tab -> Ctrl+Shift+W
Copy -> Ctrl+Shift+C
Detach Current Tab -> Ctrl+Shift+H
Enlarge Font -> Ctrl++
Expand View -> Ctrl+Shift+]
Find Next Search-> F3
Find Previous Search -> Shift+F3
Find -> Ctrl+Shift+F
Monitor for Activity -> Cttl+Shift+A
Monitor for Silence -> Ctrl+Shift+I
Move to Left Tab -> Ctrl+Shift+Left
Move to Right Tab -> Ctrl+Shift+Right
Open New Tab -> Ctrl+Shift+T
Open New Window -> Ctrl+Shift+N
Move to Next Tab -> Shift+Right
Next View Container -> Shift+Tab
None -> Ctrl+Shift+/
Paste -> Ctrl+Shift+V or Shift+Ins
Paste Selection -> Ctrl+Shift+Ins
Previous TAb -> Shift+Left
Quit -> Ctrl+Shift+Q
Rename Tab -> Ctrl+Alt+S

RUBY: Create an empty array and have array length

By Administrator on 10:36 PM in rails, ruby, rubyonrails

This will create an array with the 10 empty elements.

>> Array.new(10, '')
Output
=> ["", "", "", "", "", "", "", "", "", ""]

RUBY: Database Migration in Ruby on RAils

By Administrator on 5:22 AM in migration, ruby, rubyonrails

To run the single migration in the db.

rake db:migrate # Runs the full db migration
rake db:migrate VERSION=x #Runs the particular version

PostgreSQL: Handling the sequence value in psql(Reset sequence/ Get sequence next value)

By Administrator on 10:01 PM in PostgreSQL, psql

PostgreSQL: Reset the sequence value of the table

Example1

select setval('students_id_seq',1706);

Result

setval
--------
1706
(1 row)

===============================

Example2(Recommanded)

To reset the sequence exactly to the recent primarykey id. This is the best idea to reset the sequence by avoiding usual conflicts.

select setval('students_id_seq',(select max(id) from students))

Result

setval
--------
1706
(1 row)

===============================

PostgreSQL: Get the next sequence value of the table

select nextval('students_id_seq');

Result

nextval
---------
1707
(1 row)

RUBY: Ruby on Rails - map()

By Administrator on 10:12 PM in map, ruby, rubyonrails

dERs = Student.find(:all,:select => "id", :conditions => "")
dER_ids = dERs.map(&:id)

RUBY: Update_all in ruby on rails

By Administrator on 10:12 PM in ruby

This updates all records that mathcing with the given conditions

 People.update_all( "name = 'Joe'", "name ilike '%joe%'" )

RUBY: Craete cookie in ruby on rails

By Administrator on 4:31 AM in cookie, cookies, javascript, rails, ruby, rubyonrails

cookies[:login] = { :value => "asdf", :expires => Time.now + 600}

The above cookie will :expires in 10 min .

To Delete the Cookie in Ruby on rails:

cookies.delete :login

To Delete Cookie in Javascript:

createCookie(":login","",-1);

RUBY: Easy to create first controller in ruby on rails

By Administrator on 9:31 PM in controller, rails, ruby, rubyonrails

Create new controller in ruby on rails is the easy thing. Just follow the following process

[root]# script/generate controller <controller-name>

Sample
script/generate controller registration

this will genereate the following folders/files.

      exists app/controllers/
      exists app/helpers/
      create app/views/registration
      exists test/functional/
      create app/controllers/registration_controller.rb
      create test/functional/registration_controller_test.rb
      create app/helpers/registration_helper.rb

RUBY: slice() - ruby on rails

By Administrator on 3:47 AM in rails, ruby, rubyonrails

Slicing the string or characters from the given start position with the given length of characters.

Look at the qucik example:

        dob = '10/13/1986'
        dob_mm = dob.slice(0,2) #this returns 10
        dob_dd = dob.slice(2,2) #this returns 13
        dob_yy = dob.slice(4,4) #this returns 1986

RUBY: Lower case and upper case conversion in ruby on rails

By Administrator on 10:55 PM in lower case, rails, ruby, rubyonrails, upper case

Some of the predefined methods

"Worker".downcase #it returns "worker"
"worker".upcase #it returns "WORKER"
"worker".capitalize # this returns "Worker"

Capitalize function is very similar to the ucfirst() method in php.

LINUX: Move or rename the folder through linux command

By Administrator on 10:58 PM in linux

This performs the duo action which are move and rename.

This moves the source file from one directory to another directory.

E.g:

mv source_file_or_dir destination_file_or_dir

LINUX: Create the Symbolic links in Linux

By Administrator on 9:51 PM in linux, ruby

Symbolic links in linux is similar to shortcut file in windows.
It is higly recommended for the security reasons in linux environment.

Soft Symbolic Link:

ln -s <original-folder-path> <sympoli-file or folder name>

E.g:
ln -s /usr/local/apache/logs logs

Search and replace the the string in Javascript

By Administrator on 1:56 AM in javascript

replace(search str, replace_str): Replaces the very first occuance oif the search string.

string = 'Praise the Lord';
string = replace('Praise', 'Jesus is');
alert(string);

This returns: "Jesus is the Lord"

Implode string with ruby array values using join()

By Administrator on 9:30 AM in ruby

join() method implod the character or string between the single dimension array elements.

E.g:
x = [1,2,3,4]
x.join(",") #This returns "1,2,3,3"

RUBY: Each loop statment in ruby on rails

By Administrator on 4:30 AM in ruby

rows.each do |row|
puts row.id
end

Here rows is an array.

RUBY: Creating dynamic directory in ruby

By Administrator on 2:08 AM in ruby

system() method executes any commands that we can able to execute through terminal or konsole(console).

e.g
folder = "/tmp"
system("mkdir #{folder}") if !File.directory?(folder)

If you found any errors in the above coding , try to include the ftools library.

e.g
require 'ftools'
folder = "/tmp"
system("mkdir #{folder}") if !File.directory?(folder)

Write a file oin ruby on rails

By Administrator on 12:12 AM in

log_path = '/home/project/logs'
system("mkdir #{log_path}") if !File.directory?(log_path)
log_content = "test content"
File.open("#{log_path}/log_#{Time.now.to_i}.txt", 'a') { |file|
file.write "#{log_content}"
}

Tick Symbol HTML Decimal Codes

By Administrator on 3:06 AM in html

☐ - HTML decimal: ☐
☑ - HTML decimal: ☑
✓ - HTML decimal: ✓
✔ - HTML decimal: ✔

RUBY: Get current time stamp in ruby

By Administrator on 12:09 AM in ruby, rubyonrails, time

Getting current time is very straight forward here.

The code is


Time.now # Returns Fri Mar 08 13:27:24 +0530 2013

Time.now.to_i # Returns the unix timestamp value 1362729785

That's it.

RUBY: Ruby on Rails - string replace

By Administrator on 10:30 PM in ruby, rubyonrails

gsub

gsub() is the always very useful function in ruby.

Syntax:

string.gsub("<search char>","<replace Char>")

string.gsub(/'/,"") #replce/remove single quotes from the string

You should be careful that the string variable should not have a nil value. Otherwise it will rise a nil exception.

Ruby On Rails - Getting Started

By Administrator on 9:54 AM in ruby

Ruby on Rails, often shortened to Rails, is an open source full-stack web application framework for the Ruby programming language. Ruby on Rails runs on the general-purpose programming language Ruby, which predates it by more than a decade. Rails is a full-stack framework, meaning that it gives the web developer the ability to create pages and applications that gather information from the web server, talk to or query the database, and render templates out of the box. As a result, Rails features a routing system that is independent of the web server.

Add two Time values in php

By Administrator on 9:50 AM in php

PHP: Get full web page URL from address bar in php

By Administrator on 9:49 AM in php

There are two functions in php to get full url from address bar.

1. $_SERVER['HTTP_HOST']
2. $_SERVER['REQUEST_URI']

$_SERVER['HTTP_HOST'] this function will show only server name.
$_SERVER['REQUEST_URI'] this function will show you the path to file of your url.

Sample Code:
$url="http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];

PHP: Create CSV file format in php

By Administrator on 7:00 AM in php

fputcsv

(PHP 5 >= 5.1.0RC1)
fputcsv -- Format line as CSV and write to file pointer

Description

int fputcsv ( resource handle [, array fields [, string delimiter [, string enclosure]]] )

fputcsv() formats a line (passed as a fields array) as CSV and write it to the specified file handle. Returns the length of the written string, or FALSE on failure.
The optional delimiter parameter sets the field delimiter (one character only). Defaults as a comma: ,.
The optional enclosure parameter sets the field enclosure (one character only) and defaults to a double quotation mark: ".

Example 1. fputcsv() example



$list = array (

    'aaa,bbb,ccc,dddd',

    '123,456,789',

    '"aaa","bbb"');

$fp = fopen('file.csv', 'w');



foreach ($list as $line) {

    fputcsv($fp, split(',', $line));

}

fclose($fp);?>

What Is PHP?

By Administrator on 7:00 AM in php

What Is PHP? PHP stands for PHP: Hypertext Preprocessor, a recursive acronym. It is mainly a Web server side scripting language. But it can also be used for other purposes.

PHP was originally created by Rasmus Lerdorf in 1995 as a simple Web page generation tool named as PHP/FI (Personal Home Page/Forms Interpreter). Today it becomes the number one of server side scripting languages.

Main features of PHP:

* Cookies - PHP transparently supports HTTP cookies.
* Sessions - PHP supports sessions to allow you to preserve certain data across subsequent accesses.
* Connection handling - PHP maintains a connection in 3 possible states: NORMAL, ABORTED, and TIMEOUT.
* Using remote files - PHP allows you to open remote files with Internet protocols like HTTP or FTP.
* Persistent Database Connections - PHP supports persistent connections to database servers.
* File uploads - PHP allows Web users to upload single or multiple files.
* Safe mode - PHP supports a safe mode with many built-in functions restricted or disabled.
* Command line - PHP supports many command line options.

What is the difference between Primary Key and Unique key?

By Administrator on 6:58 AM in php

Primary Key: A column in a table whose values uniquely identify the

rows in the table. A primary key value cannot be NULL.

Unique Key: Unique Keys are used to uniquely identify each row in the

table. There can be one and only one row for each unique key value. So

NULL can be a unique key.There can be only one primary key for a table but there can be more

than one unique for a table.

PHP: Performance Tips - For Loop

By Administrator on 6:50 AM in php

Don't use for($i=0; $i<=count($arrPerson); $i++) { . . }
instead of use for($i=0,$total = count($arrPerson); $i<$total; $i++) { . . }.
The previous one will call count function for each iteration of the loop while the second one will call count function just once

PHP: What is wamp? lamp? XAMPP?

By Administrator on 6:48 AM in php

LAMP = Linux Apache MySQL PHP/Perl/Python

WAMP = Windows Apache MySQL PHP/Perl/Python

XAMPPX = (any of four different operating systems), Apache, MySQL, PHP and Perl

XAMPP's name is an acronym for:

Connect the Mysql Database from local client Computer

By Administrator on 6:47 AM in php

Create the New privilege for the Client computer name as the host name.
Then try the following sample code into your client computer,
It will be work exactly.

Sample PHP Code :
$con=mysql_connect('IP Address','root','') or die("Database Connection Failed
". mysql_error());
mysql_select_db('',$con);
$test_query=mysql_query('SELECT * FROM
'); while($row=mysql_fetch_array($test_query)) { echo $row[column].' '; } ?>

PostgreSQL: Reset the sequence value of the table

Example1

Result

setval -------- 1706(1 row)

===============================

Example2(Recommanded)

Result

setval -------- 1706(1 row)

===============================

PostgreSQL: Get the next sequence value of the table

Result

nextval --------- 1707(1 row)

fputcsv

Description

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setval
--------
1706
(1 row)

setval
--------
1706
(1 row)

nextval
---------
1707
(1 row)