Practical Web Programming

PHP: How to Get the Week Day Dates

2009-10-31T22:51:00.004-04:00

In PHP, Getting THE week day dates is not really that difficult. Using a combination of pre-defined PHP functions, you can achieve this. Here's how.

In this example function, I'll use Sunday as the start of the week. The function will accept the year, month and day - the day should be a Sunday, Ex: 2009, 10 and 25.


//FUNCTION TO GET THE WEEK DAY DATES
function get_week_day_dates($year, $month, $day)
{
    $start_of_week = mktime(0, 0, 0, $month, $day+(0-(int)date('w')), $year);
    for ($x=0; $x<7; $x++) 
    {
        print date('Y-m-d', $start_of_week + $x * 60 * 60 * 24) ."<br/>";
    }
}

//USING THE FUNCTION
get_week_day_dates(2009, 10, 25);

How to Pass Value from Javascript to PHP

2009-02-27T21:38:00.002-05:00

Although JavaScript and PHP is not the same technology, JavaScript being a client-side technology and PHP a server-side, you can actually pass values from PHP to JavaScript and vice-versa. To do this, all you need is to use a cookie.

In this example source code, I will create a cookie in JavaScript and retrieve the cookie value using PHP. Read on.

JavaScript code to create cookie.

<script type='text/javascript'>
 function createCookie(name, value,expiredays)
  {
  var expiry_date = new Date();
  expiry_date.setDate(expiry_date.getDate() + expiredays);
  document.cookie=name+ "=" +escape(value)+
                                           ((expiredays==null) ? "" 
                                           :";expires="+expiry_date.toGMTString());
  alert("'" + name + "' cookie created.");
  }
</script>

HTML code to call the createCookie function.

<input type="button" value="Create Cookie using JavaScript" 
                        onclick="createCookie('YourName', 'Joel Badinas')"/>

HTML form for submitting request to the server for the PHP code.

<form method="POST" action=""> 
<p>
<input type="submit" name="submit" value="Get Cookie using PHP"/>
</p>
</form>

PHP code that will read the cookie.

<?php
if (isset($_POST["submit"]))
 {
 print "Cookie value is '".$_COOKIE["YourName"]."'";
 }
?>

Putting it all together.

<html>
<head>
<title>Practical Web Programming</title>

<script type='text/javascript'>
 function createCookie(name, value,expiredays)
  {
  var expiry_date = new Date();
  expiry_date.setDate(expiry_date.getDate() + expiredays);
  document.cookie=name+ "=" +escape(value)+
                                           ((expiredays==null) ? "" 
                                           :";expires="+expiry_date.toGMTString());
  alert("'" + name + "' cookie created.");
  }
</script>

</style>

</head>
<body>

<p method="POST" action=""> 
<p>
<input type="button" value="Create Cookie using JavaScript" 
                        onclick="createCookie('YourName', 'Joel Badinas')"/>
<input type="submit" name="submit" value="Get Cookie using PHP"/>
</p>
</form>

<?php
if (isset($_POST["submit"]))
 {
 print "Cookie value is '".$_COOKIE["YourName"]."'";
 }
?>

</body>
</html>

There you have it.

PHP: How to Get the Time Elaped

2009-02-19T22:40:00.006-05:00

Using PHP's time function, you can get the time elapsed of any process in your web application. The time function returns the current Unix timestamp.

Here's a simple script to demonstrate it.


<?php

$t1 = time();

print "Start time : ".$t1."<br>";

for ($i = 0; $i < 90000000; $i++)
    {
    print "";
    }

$t2 = time();
print "End time : ".$t2."<br>";
print "Time elapsed (s) : ".($t2 - $t1)."<br>";

?>

The script above will output the following.


Start time : 1235100956
End time : 1235100980
Time elapsed (s) : 24

Solved: Can't Change Blogger Blog Shortcut Icon

2009-02-15T11:50:00.005-05:00

Ok, you followed my instructions on how to change your blog/website shortcut icon but your Blogger blog is still showing the default Blogger shortcut logo. Don't despair, you are not alone. I myself was in that situation before when I tried to change this blog's shortcut icon.

In your Blogger template head tag section, you will see a b:include tag named all-head-content (highlighted in red) . When your is blog is visited (or loaded in HTML), the Blogger engine will replace that tag with all the meta tags for you blog including the shortcut icon, and you have no control over this.

<head>
  <b:include data='blog' name='all-head-content'/>
  <title><data:blog.pageTitle/></title>
  <b:skin><![CDATA[/*

Fortunately, I found a simple trick to outsmart Blogger. When you insert your HTML shortcut icon code, put it after the b:include tag named all-head-content. Here's an example from this blog.

<head>
  <b:include data='blog' name='all-head-content'/>
  <title><data:blog.pageTitle/></title>
  <link href='http://kabalweg.googlepages.com/joelbadinas.com.ico' rel='shortcut icon'/>
  <b:skin><![CDATA[/*

Doing it this way will override the shortcut icon from the Blogger enginge.

PHP: How to Get the Last Element of an Array

2009-01-30T08:34:00.003-05:00

If you know it's length, getting the last element of an array is easy. You just put the index of the last element and you have it's value. But what if you don't know it's length or your array is populated at runtime and it's length is dynamic? Now you got a problem :).

To solve this, you also need a dynamic approach. Using PHP's count function, you can dynamically get the last element of an array. Here's how.

<?php

//Getting the last element of an array dynamically

$arr = array("one", "two", "three", "four", "five");
print "Last element: " . $arr[count($arr) -1];

?>

Take note that in PHP, arrays starts at 0, so if you have five elements, the index of the first element is 0 and the last's is 4. So the code count($arr) will return 5, while count($arr) - 1 will return 4.

Types of Loops in PHP

2009-01-29T05:57:00.000-05:00

A programming loop is a sequence of statements which is specified once but can also be performed several times in succession. Looping construct is one of the most powerful feature of all programming language. Using loops, you can duplicate task to any number of repetitions.

If PHP, this are four types of looping construct, the while, do...while, for and foreach loop. The following example demonstrates how to use each loop.

Using the while loop.

<?php

$x=1;
while($x<=10)
  {
  echo "The number is " . $x . "<br />";
  $x++;
  }

?>

while loop output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5
The number is 6
The number is 7
The number is 8
The number is 9
The number is 10

Using the do...while loop.

<?php

$x=1;
do
  {
  echo "The number is " . $x . "<br />";
  $x++;
  }
while ($x<10);

?>

do...while loop output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5
The number is 6
The number is 7
The number is 8
The number is 9

Using the for loop.

<?php

for ($x=1; $x<=10; $x++)
  {
  echo "The number is " . $x . "<br />";
  }

?>

for loop output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5
The number is 6
The number is 7
The number is 8
The number is 9
The number is 10

Using the foreach loop.

<?php

$arr=array("one", "two", "three", "four", "five");
foreach ($arr as $value)
  {
  echo "Value: " . $value . "<br />";
  }

?>

foreach loop output:

Value: one
Value: two
Value: three
Value: four
Value: five

PHP: How to Parse XML Using the DOMDocument Class

2009-01-28T06:14:00.009-05:00

I this example, I will show you how to parse (or read) XML documents using PHP. I will be using the XML that I created in the Output MySQL Records to XML Using PHP post.

To parse XML, I will be using PHP's DOMDocument class. Here's the example.

<?php

//CREATE AN INSTANCE OF DOMDocument() CLASS
$doc = new DOMDocument();

//LOAD THE XML
$doc->loadXML($xml);

//READ THE <employee> AND LOOP THROUGH IT

$employees = $doc->getElementsByTagName("employee");
foreach($employees as $employee)
  {
  //READ THE <firstname> AND GET THE NODE VALUE
  $firstnames = $employee->getElementsByTagName("firstname");
  $firstname = $firstnames->item(0)->nodeValue; 
  
  //READ THE <lastname> AND GET THE NODE VALUE
  $lastnames = $employee->getElementsByTagName("lastname");
  $lastname = $lastnames->item(0)->nodeValue;   

  //DISPLAY IT
  print $firstname." ".$lastname."<br/>";
  }

?>

The above source code will have the following output.

Steven King
Neena Kochhar
Lex De Haan
Alexander Hunold
Bruce Ernst
David Austin
Valli Pataballa
Diana Lorentz
Nancy Greenberg
Daniel Faviet
John Chen
Ismael Sciarra
Jose Manuel Urman
Luis Popp
Den Raphaely
Alexander Khoo
Shelli Baida
Sigal Tobias
Guy Himuro
Karen Colmenares
Matthew Weiss

If you want to parse an physical XML file (an XML file that is saved in your server), use load rather than loadXML.

PHP: How to Create XML Document from MySQL Records

2009-01-27T08:57:00.009-05:00

In this example, I'll be showing how to create XML document from MySQL records using PHP.

XML (Extensible Markup Language) is a general-purpose specification for creating custom markup languages. Aside from creating web pages, the most important use of XML is data sharing. Using XML you can pass data to different computer and applications without it being converted into another form.

Fortunately for PHP developers, creating XML from MySQL data is just like creating HTML. I'll be using the database table from this post. Here's the source codes.

<?php

//CREATE A DATABASE CONNECTION
$db_conn = mysql_connect("localhost", "root", "root1") 
           or die("Cannot connect to the database. ".mysql_error()); 
//SELECT THE DATABASE TO USE
mysql_select_db("test");

$sql = "SELECT
           first_name, last_name, email
        FROM employees";

$result = mysql_query($sql, $db_conn);

$xml = "<?xml version='1.0' encoding='UTF-8'?>
 <employees>";
while ($row = mysql_fetch_assoc($result))
    {
 $xml .= "<employee>";
 $xml .= "<firstname>".$row["first_name"]."</firstname>";
 $xml .= "<lastname>".$row["last_name"]."</lastname>";
 $xml .= "</employee>";
    }
$xml .= "</employees>";

//DISPLAY THE XML
print $xml;

?>

This will output the following. I added line breaks (using enter key) at the end of every </employee> tags to make it more readable.

<?xml version='1.0' encoding='UTF-8'?>
<employees>
<employee><firstname>Steven</firstname><lastname>King</lastname></employee>
<employee><firstname>Neena</firstname><lastname>Kochhar</lastname></employee>
<employee><firstname>Lex</firstname><lastname>De Haan</lastname></employee>
<employee><firstname>Alexander</firstname><lastname>Hunold</lastname></employee>
<employee><firstname>Bruce</firstname><lastname>Ernst</lastname></employee>
<employee><firstname>David</firstname><lastname>Austin</lastname></employee>
<employee><firstname>Valli</firstname><lastname>Pataballa</lastname></employee>
<employee><firstname>Diana</firstname><lastname>Lorentz</lastname></employee>
<employee><firstname>Nancy</firstname><lastname>Greenberg</lastname></employee>
<employee><firstname>Daniel</firstname><lastname>Faviet</lastname></employee>
<employee><firstname>John</firstname><lastname>Chen</lastname></employee>
<employee><firstname>Ismael</firstname><lastname>Sciarra</lastname></employee>
<employee><firstname>Jose Manuel</firstname><lastname>Urman</lastname></employee>
<employee><firstname>Luis</firstname><lastname>Popp</lastname></employee>
<employee><firstname>Den</firstname><lastname>Raphaely</lastname></employee>
<employee><firstname>Alexander</firstname><lastname>Khoo</lastname></employee>
<employee><firstname>Shelli</firstname><lastname>Baida</lastname></employee>
<employee><firstname>Sigal</firstname><lastname>Tobias</lastname></employee>
<employee><firstname>Guy</firstname><lastname>Himuro</lastname></employee>
<employee><firstname>Karen</firstname><lastname>Colmenares</lastname></employee>
<employee><firstname>Matthew</firstname><lastname>Weiss</lastname></employee>
</employees>

Note: To view the full output, right click on the browser and select 'View Source' or 'View Page Source'.

PHP: How to Print Each Character in a String

2009-01-26T08:22:00.000-05:00

With PHP's growing string functions, you will be able to find one that will suit your need. For instance the substr, this function will return the portion of string specified by the start and length parameters. You can you use it to print each character in a string.

Here's an example.

    
$string = "Joel P. Badinas";

for ($i = 0; $i < strlen($string); $i++)
    {
    print "[" . $i . "] " . substr($string, $i, 1) ."<br/>";    
    }

?>

The output will be like this.

  [0]  J
  [1]  o
  [2]  e
  [3]  l
  [4]  
  [5]  P
  [6]  .
  [7]  
  [8]  B
  [9]  a
  [10]  d
  [11]  i
  [12]  n
  [13]  a
  [14]  s

Database Insert, Update and Delete Using PHP and MySQL

2009-01-25T15:59:00.000-05:00

One of the best uses of PHP to the MySQL database is data manipulation. PHP's native support to MySQL is a big advantage to developers who uses the two. Once you got PHP and MySQL running in your server, you're good to go toward dynamic web application.

In the following examples, I'll be focusing on how to do data INSERT, UPDATE, and DELETE to the database using the web's two powerful combination, PHP and MySQL.

Here's the first one, doing data INSERT to the database. In these examples, I use the table from this post which I created in the test database in MySQL.

<?php

//CREATE A DATABASE CONNECTION
$db_conn = mysql_connect("localhost", "root", "root1") 
           or die("Cannot connect to the database. ".mysql_error());  
//SELECT THE DATABASE TO USE
mysql_select_db("test");

//COMPOSE THE SQL
$sql = "INSERT INTO employees (
    first_name, 
    last_name, 
    email,
    phone_number)
  VALUES (
    'Joel',
    'Badinas',
    'kabalweg@gmail.com',
    '123.456.7890')";
    
//EXECUTE SQL
$result = mysql_query($sql, $db_conn);

//CHECK IF QUERY IS SUCCESSFUL
if(mysql_affected_rows($db_conn) > 0)
  {
  print "Save successful";
  }
else
  {
  print "Error: ".mysql_error();
  }

?>

And here's how to do the data Update.

<?php

//CREATE A DATABASE CONNECTION
$db_conn = mysql_connect("localhost", "root", "root1") 
           or die("Cannot connect to the database. ".mysql_error());  
//SELECT THE DATABASE TO USE
mysql_select_db("test");

//COMPOSE THE SQL
$sql = "UPDATE employees SET 
    first_name = 'Kabalweg' 
  WHERE first_name = 'Joel' 
  AND   last_name = 'Badinas'";

//EXECUTE SQL
$result = mysql_query($sql, $db_conn);

//CHECK IF QUERY IS SUCCESSFUL
if(mysql_affected_rows($db_conn) > 0)
  {
  print "Update successful";
  }
else
  {
  print "Error: ".mysql_error();
  }

?>

And the last is the DELETE.

<?php

//CREATE A DATABASE CONNECTION
$db_conn = mysql_connect("localhost", "root", "root1") 
           or die("Cannot connect to the database. ".mysql_error());  
//SELECT THE DATABASE TO USE
mysql_select_db("test");

//COMPOSE THE SQL
$sql = "DELETE FROM employees 
  WHERE first_name = 'Kabalweg' 
  AND   last_name = 'Badinas'";

//EXECUTE SQL
$result = mysql_query($sql, $db_conn);

//CHECK IF QUERY IS SUCCESSFUL
if(mysql_affected_rows($db_conn) > 0)
  {
  print "Delete successful";
  }
else
  {
  print "Error: ".mysql_error();
  }

?>

There you have it. The source codes are well commented so you should be able to follow. If not, post a question in the comment.

How to Redirect a Web Page Using HTML

2009-01-24T08:34:00.004-05:00

How to redirect a web page using HTML is just easy as redirect in PHP. While in PHP we use the header function, in HTML, we use the meta tag to accomplish the same task.

Here's an example.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
  <head>
    <title>HTML Redirect in Meta Tag</title>
    <meta http-equiv="REFRESH" content="0;url=http://localhost/redirect.php">
  </head>

  <body>
  
  </body>
</html>

In HTML redirection, the content attribute of the meta tag should contain the number of seconds to pause before doing the redirection and the page where to redirect. The above sourcecode will redirect the current page to http://localhost/redirect.php in 0 second.

If you want to notify your visitor before redirecting, you can specify the number of seconds to pause. This way, you can display a message in your current page.

Here's how.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
  <head>
    <title>HTML Redirect in Meta Tag</title>
    <meta http-equiv="REFRESH" content="5;url=http://localhost/redirect.php">
  </head>

  <body>
    
    <p>This page will redirect in 5 seconds...</p>
  
  </body>
</html>

How to Submit an HTML Form to a New Window

2009-01-23T00:32:00.005-05:00

Sometimes, for whatever reason, you want to submit an HTML form to a new window. To do this, you just need to add the attribute target='_blank' to your HTML form. Here's an example.

<form target='_blank' method='POST' action='index.php'>
   <br/>First Name: <input type='text' name='firstname' value='' />
   <br/>Last Name: <input type='text' name='lastname' value='' />
   <br/><input type='submit' name='submit' value='Submit' />
</form>

And here's the PHP version.

<?php

print "<form target='_blank' method='POST' action='index.php'>
         <br/>First Name: <input type='text' name='firstname' value='' />
         <br/>Last Name: <input type='text' name='lastname' value='' />
         <br/><input type='submit' name='submit' value='Submit' />
       </form>";

?>

Once you click the Submit button, the browser will submit and open a new window where the form will be handled.

PHP: Using foreach to Loop Through Array

2009-01-22T08:29:00.004-05:00

The foreach looping construct in one of the less used looping construnct in the programming language, and PHP is not an exception. This is because in PHP, the foreach works only with arrays and will spit an error if used with other data type.

Anyways, using the foreach loop construct is really easy. See example below.

$array = array("j", "o", "e", "l", "b", "a", "d", "i", "n", "a", "s");

foreach ($array as $char)
    {
    print $char."<br/>";
    }

The above example will output below.

j
o
e
l
b
a
d
i
n
a
s

How to Truncate Text in PHP

2009-01-21T07:51:00.004-05:00

Here's a simple tutorial on how to truncate text in PHP. In this tutorial, I'll be using the substr function. See the sourcecode below.

<?php

$text = 'The quick brown fox jumps over the lazy dog';
$truncated1 = substr($text, 0, 20);
$truncated2 = substr($text, 20, 40);

print "<br/>The original text: ". $text;
print "<br/>The truncated text 1: ". $truncated1;
print "<br/>The truncated text 2: ". $truncated2;

?>

Using the substr function, you can truncate a text to whatever length you want by changing the third parameter and also change the start position by changing the second parameter.

The above PHP script will output the following:

The original text: The quick brown fox jumps over the lazy dog
The truncated text 1: The quick brown fox
The truncated text 2: jumps over the lazy dog

Simple PHP and Ajax Tutorial

2009-01-16T08:38:00.006-05:00

When I was beginning web development, Ajax was all blur to me. Whenever I need Ajax functionality for my PHP project, I would go to the web and search to similar Ajax examples that fit need. Although today I'm not yet a master of this WEB 2.0 technique, I can say I passed the beginner stage.

In PHP, a simple, yet powerful implementation of Ajax is querying and displaying the result of a database query. This makes your web application run faster than just pure PHP because the browser don't have to load.

This simple PHP and Ajax tutorial is composed of three files, namely, index.php, ajax.js and ajax.php. I will be using the database from this post.

Here's the index.php. This file contains the HTML codes and the container in which the result of the query will be displayed.

<html>

<head>
    <title>A Simple PHP-Ajax Tutotial</title>
    <script src="ajax.js"></script>
</head>

<body>

<br/><input type='button' value='Query' onclick='queryDb()' name='Query' /><br/>

<div id='container'></div>

</body>
</html>

The ajax.js file contains the Javascript code.

//CREATE A VARIABLE THAT WILL HOLD THE XMLHttpRequest OBJECT
request = null;

//THIS FUNCTION WILL CREATE AN INSTANCE OF XMLHttpRequest OBJECT 
AND RETURN IT TO THE CALLING FUNCTION
function GetXmlHttpObject()
    {
    var xmlHttp=null;
    try
        {
        // Firefox, Opera 8.0+, Safari
        xmlHttp=new XMLHttpRequest();
         }
    catch (e)
         {
         //Internet Explorer
         try
              {
              xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
              }
         catch (e)
              {
              xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
              }
         }
    return xmlHttp;
    }

//THIS FUNCTION WILL CALL THE GetXmlHttpObject() FUNCTION AND THE ajax.php PAGE
function queryDb()
    {
    //DISPLAY THE 'LOADING' TEXT IN THE DIV CONTAINER
    document.getElementById("container").innerHTML = "Loading";
    //CREATE AN INSTANCE OF XMLHttpRequest OBJECT
    request = GetXmlHttpObject();
    //SET queryDone FUNCTION TO THE onreadystatechange EVENT
    request.onreadystatechange = queryDone;
    //OPEN THE PHP PAGE USING THE POST METHOD
    request.open("POST", "ajax.php", true);
    //SEND THE REQUEST
    request.send(null);
    }

//HELPER FUNCTION FOR queryDb()
function queryDone()
    {
    if (request.readyState == 4)
        {
        if (request.status == 200 || request.status == 304)
            {
            //GET THE RESPONSE FROM THE PHP PAGE
            results = request.responseText;
            //DISPLAY THE RESPONSE IN THE DIV CONTAINER
            document.getElementById("container").innerHTML = results;
            }
        else
            {
            //IF A ERROR OCCUR, DISPLAY IT IN THE DIV CONTAINER
            document.getElementById("container").innerHTML = "ajax error:\n" + request.statusText;
            }
        }
    }

The ajax.php file contains the PHP code that will connect and query the database. It will display the result of the query using the print function, which will in turn will be passed by the Javascript code to the HTML container.

<?php

//CONNECT TO MYSQL DATABASE
$con = mysql_connect("localhost", "root", "root1") 
       or die("<p class='error-msg'>Cannot connect to the database. ".mysql_error()."</p>");            

//SELECT A DATABASE
mysql_select_db("test");

//COMPOSE QUERY
$sql = "
          SELECT
           CONCAT(first_name, ' ', last_name) AS name
          FROM employees
          LIMIT 0, 10";

//print "<pre>".$sql."</pre>";
            
//EXECUTE THE QUERY
$result = mysql_query($sql, $con);

while ($row = mysql_fetch_assoc($result))
    {
    print "<br/>".$row["name"];
    }

?>

To run this example, copy and paste the sourcecodes above, name it index.php, ajax.js and ajax.php respectively and save it in the same folder of your server.

PHP: How to Delete the First and Last Character in a String

2009-01-15T07:10:00.003-05:00

Using PHP's substr and strlen functions, you can delete the first and last character in a string. Here's the syntax of the functions from the PHP documentation website.

string substr  ( string $string  , int $start  [, int $length  ] )

int strlen  ( string $string  )

substr returns a part of a string, while strlen returns the length of a string. See below for the example.

<?php

$my_name = "Joel Badinas";
$str_length = strlen($my_name);

$no_first_char = substr($my_name, 1, $str_length);
$no_last_char = substr($my_name, 0, $str_lenght - 1);

print ("Original String       : " . $my_name . "<br/>");
print ("No first character: " . $no_first_char . "<br/>");
print ("No last character: " . $no_last_char . "<br/>");

?>

The above source code will display the following:

Original String : Joel Badinas
No first character: oel Badinas
No last character: Joel Badina

PHP and MySQL Search/Browse Pagination Tutorial

2009-01-12T21:30:00.003-05:00

Pagination in a website is very useful, especially in a search or browse page. In fact, almost all website with search pages utilize this technique. And no other websites other than search engines benefit from this. Here's simple implementation of Google.

That being said, it's time you add this feature to you blog or website. Fortunately for us, search and browse pagination in PHP and MySQL in fairly easy, thanks to MySQL's LIMIT keyword that you can use in SELET queries.

In this tutorial, I'm going to use the database from this post.

Start by setting the size or the number of rows of each page.

$page_size = 10;

Connect to the database and select the database to use.

$con = mysql_connect("localhost", "root", "root1") 
  or die("Cannot connect to the database. ".mysql_error().");           

mysql_select_db("test");

Using MySQL's CEILING function, count the number of pages by dividing the rows with the $page_size variable we declared earlier.

//COMPOSE QUERY
$sql = "SELECT
          CEILING(count(1) / ".$page_size.") AS count
        FROM employees";

$result = mysql_query($sql, $con);

if ($row = mysql_fetch_assoc($result))
    {
    $page_count = $row["count"];
    }

Using the HTML <a> tag, display the number of pages.

for ($i = 1; $i < $page_count + 1; $i++)
    {
    print "<a href='?page=".$i."'>".$i."</a>  ";
    }

Check if the GET variable, page, is available and set the $limit variable.

if (isset($_GET["page"]))   
    {
    $page_no = $_GET["page"];
    $limit =  ($page_no * $page_size) - $page_size;
    }
else
    {
    $limit =  0;
    }

Compose and execute the query and display the result.

$sql = "SELECT
           CONCAT(first_name, ' ', last_name) AS name
        FROM employees
        LIMIT ".$limit .", ".$page_size;

          
$result = mysql_query($sql, $con);

print "<br/>";
while ($row = mysql_fetch_assoc($result))
    {
    print "<br/>".$row["name"];
    }

Here's the complete code.

//SET THE ROWS FOR EVERY PAGE
$page_size = 10;
   
//CONNECT TO MYSQL DATABASE
$con = mysql_connect("localhost", "root", "crop") 
  or die("<p class='error-msg'>Cannot connect to the database. ".mysql_error()."</p>");           

//SELECT A DATABASE
mysql_select_db("test");

//COMPOSE QUERY
$sql = "SELECT
             CEILING(count(1) / ".$page_size.") AS count
            FROM employees";

//EXECUTE THE QUERY
$result = mysql_query($sql, $con);

if ($row = mysql_fetch_assoc($result))
    {
    $page_count = $row["count"];
    }

//DISPLAY A LINK TO THE NUMBER OF PAGES
for ($i = 1; $i < $page_count + 1; $i++)
    {
    print "<a href='?page=".$i."'>".$i."</a>  ";
    }

//CHECK IF PAGE VARIABLE IS AVAILABLE AND CALCULATE THE LIMIT
if (isset($_GET["page"]))   
    {
    $page_no = $_GET["page"];
    $limit =  ($page_no * $page_size) - $page_size;
    }
else
    {
    $limit =  0;
    }

//COMPOSE QUERY
$sql = "SELECT
           CONCAT(first_name, ' ', last_name) AS name
        FROM employees
        LIMIT ".$limit .", ".$page_size;

          
//EXECUTE THE QUERY
$result = mysql_query($sql, $con);

print "<br/>";
while ($row = mysql_fetch_assoc($result))
    {
    print "<br/>".$row["name"];
    }

If you follow my example above, you should be able to see the result like this.

SQL: How to Copy the Database Table Definition and Data Using SQL Scripts

2009-01-07T21:25:00.006-05:00

Here are simple, yet powerful SQL scripts to copy the entire definition and data of a database table. These SQL scripts are useful if you are making a backup of a table without a GUI. The only drawback of using these, is that it doesn't copy the keys and constraints of the table. But personally, I prefer using these scripts when I make a backup than using a GUI because it's so simple and I get to practice my SQL :). See below.

First, let's create a table for this tutorial using SQL.

CREATE TABLE IF NOT EXISTS `employees` (
  `employee_id` int(10) unsigned NOT NULL auto_increment,
  `first_name` varchar(30) NOT NULL,
  `last_name` varchar(30) NOT NULL,
  `email` varchar(50) NOT NULL,
  `phone_number` varchar(15) NOT NULL,
  PRIMARY KEY  (`employee_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=121;

Then, we insert records to the table using SQL again.

INSERT INTO `employees` (
`employee_id`, `first_name`, `last_name`, `email`, `phone_number`) 
VALUES
(100, 'Steven', 'King', 'SKING', '515.123.4567'),
(101, 'Neena', 'Kochhar', 'NKOCHHAR', '515.123.4568'),
(102, 'Lex', 'De Haan', 'LDEHAAN', '515.123.4569'),
(103, 'Alexander', 'Hunold', 'AHUNOLD', '590.423.4567'),
(104, 'Bruce', 'Ernst', 'BERNST', '590.423.4568'),
(105, 'David', 'Austin', 'DAUSTIN', '590.423.4569'),
(106, 'Valli', 'Pataballa', 'VPATABAL', '590.423.4560'),
(107, 'Diana', 'Lorentz', 'DLORENTZ', '590.423.5567'),
(108, 'Nancy', 'Greenberg', 'NGREENBE', '515.124.4569'),
(109, 'Daniel', 'Faviet', 'DFAVIET', '515.124.4169'),
(110, 'John', 'Chen', 'JCHEN', '515.124.4269'),
(111, 'Ismael', 'Sciarra', 'ISCIARRA', '515.124.4369'),
(112, 'Jose Manuel', 'Urman', 'JMURMAN', '515.124.4469'),
(113, 'Luis', 'Popp', 'LPOPP', '515.124.4567'),
(114, 'Den', 'Raphaely', 'DRAPHEAL', '515.127.4561'),
(115, 'Alexander', 'Khoo', 'AKHOO', '515.127.4562'),
(116, 'Shelli', 'Baida', 'SBAIDA', '515.127.4563'),
(117, 'Sigal', 'Tobias', 'STOBIAS', '515.127.4564'),
(118, 'Guy', 'Himuro', 'GHIMURO', '515.127.4565'),
(119, 'Karen', 'Colmenares', 'KCOLMENA', '515.127.4566'),
(120, 'Matthew', 'Weiss', 'MWEISS', '650.123.1234');

Now, let's copy the table data including the definition.

CREATE TABLE emp AS SELECT * FROM employees

Here's to copy the table definition without the data

CREATE TABLE emp AS SELECT * FROM employees WHERE 1 = 0

And here's to copy the seleted table data including the definition using MySQL's LIMIT

CREATE TABLE emp AS SELECT * FROM employees LIMIT 0, 10

And the last but not least, let's copy the seleted table column including the definition

CREATE TABLE emp AS SELECT first_name, last_name FROM employees

The last four SQL scripts about creates a table named emp from the result of the SELECT statement.

There are other variations of the CREATE TABLE [table] AS SELECT statements that I haven't included here, some of them I don't know yet. I'll update this post as soon as I find more.

PHP: How to Format Date Using date and strtotime Functions

2009-01-06T22:36:00.002-05:00

In PHP formatting a date to your desired format is so easy using the date and strtotime functions.

According to the PHP documentation strtotime parses any English textual datetime description into a Unix timestamp. It expects to be given a string containing a US English date format and will try to parse that format into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 UTC)

Syntax:

int strtotime  ( string $time  [, int $now  ] )

Example:

print strtotime("Dec. 25, 2008 10:00 AM");

The date function on the other hand returns a string formatted time/date according to the given format string using the given integer timestamp or the current time if no timestamp is given.

Syntax:

string date  ( string $format  [, int $timestamp  ] )

Example:

print date("M d, Y H:i:s A");

So much for the long explanation. Here's how to format a date using the both functions.

print date("M d, Y H:i:s A", strtotime("Dec. 25, 2008 10:00 AM"));

For the complete list of format for the date functions, visit the PHP documentation here.

PHP: How to Dynamically Alternate the Table Row Background Color

2008-12-30T07:40:00.005-05:00

In PHP, making the <table> row background color alternate dynamically is relatively easy. The key here is PHP's modulo (%) operator. Using the % operator inside a loop construct, you can reference every other row in an HTML <table>. See the example below.

Create the CSS rules.

.alt-color-1{
 background-color:red;
}

.alt-color-2{
 background-color:green;
}

Create the PHP script.

<?php
print "<table width='200' border='1' cellspacing='1' cellpadding='1'>";
for ($i = 0; $i < 10; $i++)
{
if (($i % 2) == 0)
 {
 $alt = "alt-color-1";
 }
else
 {
 $alt = "alt-color-2";
 }

print "<tr class='".$alt."'>";
print "<td>".$i."</td>";
print "<td>".$i."</td>";
print "</tr>";
}
print "</table>";
?>

Put it all together.

<html>
<head>
<title>Alternate Color in Table Rows</title>

<style>
.alt-color-1{
 background-color:red;
}
.alt-color-2{
 background-color:green;
}
</style>

</head>
<body>

<?php
print "<table width='200' border='1' cellspacing='1' cellpadding='1'>";

for ($i = 0; $i < 10; $i++)
{
if (($i % 2) == 0) //USE THE MODULO OPERATOR
 {
 $alt = "alt-color-1";
 }
else
 {
 $alt = "alt-color-2";
 }

print "<tr class='".$alt."'>";
print "<td>".$i."</td>";
print "<td>".$i."</td>";
print "</tr>";
}
print "</table>";
?>

</body>
</html>

After executing the PHP script, here's what the webpage will look.

PHP: How to Display The Current Month in Calendar Style

2008-12-26T22:57:00.007-05:00

Displaying the current month in a calendar style is very handy and user-friendly for a website, specially for a blog. Using a calendar-style navigation your visitors can easily navigate through your previous posts and articles.

Fortunately, in PHP, this seemingly difficult task in HTML is relatively easy. Just by using a nested For Loop and PHP's Date functions, use can build your own calendar.

Here's the simple source code.

<?php
  $now = getdate(time());
  $time = mktime(0,0,0, $now['mon'], 1, $now['year']);
  $date = getdate($time);
  $dayTotal = cal_days_in_month(0, $date['mon'], $date['year']);
  
  print '<table><tr><td colspan="7"><strong>' . $date['month'] . '</strong></td></tr>';
  for ($i = 0; $i < 6; $i++) 
    {
    print '<tr>';
    for ($j = 1; $j <= 7; $j++) 
      {
      $dayNum = $j + $i*7 - $date['wday'];      
      print '<td';
      if ($dayNum > 0 && $dayNum <= $dayTotal) 
        {
        print ($dayNum == $now['mday']) ? ' style="background: #aaa;">' : '>';
        print $dayNum;
        }
      else 
        {
        print '>';
        }
      print '</td>';
      }
    print '</tr>';
    if ($dayNum >= $dayTotal && $i != 6)
      {
      break;
      }
    }
  print '</table>';
?>

Here's how the calendar will look like.

To make it fancier, all you have to do now is use CSS to add colors and styles.

My First Ubuntu Machine, and I'm Loving it

2008-12-21T11:29:00.002-05:00

My first encounter with Ubuntu was more than a year ago. Back then I was using Windows XP both at work and at home. By then, I tried installing it as a secondary boot in my XP desktop at home but it just wouldn't load after the installation so I didn't force it.

More than two weeks ago, I finally completed my desktop. It took me more than a month to build because I have to wait the parts (LCD monitor, casing, keyboard, mouse and power supply) that I bought from Amazon. I can say that it's worth the wait because this is my first Ubuntu machine and I'm loving it. I got Ubuntu 8.10 installed in it.

Though I am Windows user ever since, it wasn't difficult for to adjust to this new operating system. Like Windows, Ubuntu comes with softwares that you can use for your daily tasks. My problem with this OS is my printer is not working on it. Fortunately, I got a Macbook to print with. Other than that, I'm head over heels with it.

With this first taste of Linux, I think I will not go back to Windows if given a choice.

PHP: Checking If Email is Valid with filter_var Function

2008-12-20T23:03:00.003-05:00

In PHP 4, checking if an email is valid uses regular expressions. But with PHP 5, you can use the filter_var function. This function returns the filtered data, or false if the filter fails.

Here's the syntax.

mixed filter_var ( mixed $variable [, int $filter [, mixed $options ]] )

Where:
variable = Value to filter.
filter   = ID of a filter to use. Defaults to FILTER_SANITIZE_STRING.
options  = Associative array of options or bitwise disjunction of flags.

Here's how to use the function.

if (filter_var(trim($email), FILTER_VALIDATE_EMAIL))
  {
  echo $email . " is valid.";
  }
else
  {
  echo $email . " is invalid.";
  }

Iraqi Reporter Throws Shoe to Us President George Bush

2008-12-16T09:20:00.004-05:00

I was in the office yesterday when I saw this video of an Iragi reporter throws his shoes to the Us President George Bush on CNN.

Although this is a grave insult to the US president and things like these in the US is a federal offense, some says this is a good sign that democracy is slowly creeping in Iraq. Things like these didn't exist in Saddam Hussein's dictatorial government because they will surely behead the suspect without even an investigation.

PHP: A Simple Function to Create an HTML Select Date Options

2008-12-05T07:43:00.012-05:00

Here's a simple PHP function to create a select date options that you can use in your HTML forms to let users select a date. This is simple and easy to use. Below is the function definition.

//RETURN DATE OPTIONS IN HTML
function get_date_options($year = 0000, $month = 00, $day = 00)
 {
 $ret_val = "";

 //ASSEMBLE MONTHS
 $options = "<option value='00'>MM</option>";
 for ($i = 1; $i < 13; $i++)
   {   
   $attribute = "value='".$i."'";
   if ($i == $month)
     {
     $attribute .= " selected ";
     }
   $options .= "<option ".$attribute.">".str_pad($i,2,0,STR_PAD_LEFT)."</option>";
   } 
 $ret_val .=  "<select name='month'>".$options."</select> / ";

 //ASSEMBLE DAYS
 $options = "<option value='00'>DD</option>";
 for ($i = 1; $i < 32; $i++)
   {
   $attribute = "value='".$i."'";
   if ($i == $day)
     {
     $attribute .= " selected ";
     }
   $options .= "<option ".$attribute.">".str_pad($i,2,0,STR_PAD_LEFT)."</option>";
   } 
 $ret_val .=  "<select name='day'>".$options."</select> / ";

 //ASSEMBLE YEARS
 $options = "<option value='0000'>YYYY</option>";
 for ($i = 2008; $i < 2051; $i++)
   {
   $attribute = "value='".$i."'";
   if ($i == $year)
     {
     $attribute .= " selected ";
     }
   $options .= "<option ".$attribute.">".$i."</option>";
   } 
 $ret_val .=  "<select name='year'>".$options."</select>";

 return $ret_val;
 }

Here's a simple way to use it.

Enter your birthday : <?php print get_date_options() ?>

And here's a way to use it to make default to a date.

Enter your birthday : <?php print get_date_options("2008", "12", "05") ?>