PHP Programming 101

(cont….)

V. Operators in PHP

*Arithmetic Operators*

+ addition
- subtraction
* multiplication
/ division
% modulus (division remainder)
++ increment
– decrement

*Comparison Operators*
== equal to
!= not equal
> greater than
= greater than or equal
<= less than or equal

*Logical Operators*
&& and
|| or
! not

I know its self explanatory…

VI. IF….Else Statements

If (condition)
//*Things to be executed if the answer to the condition is true*//
else
//*Things to be executed if the answer to the condition is false*//

If…else statement is use if the user wants to execute a set of code when the condition is true and another if the condition is not true.

VII. Switch Statement

switch (expression)
{
case 1:
//*code to be executed*//
break;
case 2:
//*code to be executed*//
break;
default:
//*code to be executed*//
break;
}

Switch statement is use if you want to select one of many blocks of code to be executed. this statement is used to avoid long blocks of if…elseif..else.

VIII. Looping Statement

while(condition)
code to be executed;

While statement is used to execute a block of code if and as long as a condition is true

do
{
code to be executed;
}while (condition)

Do—while statement is used to execute a block of code at least once and it will repeat the loop as long as the condition is true.

for each (array as value)
{
code to be executed;
}

For each statement is used to loop through arrays.

I think this is already enough and it has added new knowledge to those who are new in PHP… good luck and happy coding…

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(cont…)
III. PHP Variables

$variablename=value;

Variables are used for storing values such as text string or arrays. And all variables in PHP starts with a ($) dollar sign. There are various rules to be follow before naming a variable. 1) A variable name must start with a letter or an underscore. 2) A variable name can only contain alpha-numeric characters and underscores. Special characters are not allowed. 3) A variable name should not contain spaces.

IV.PHP Strings

$wrd=”Hello World”;
print $wrd;

Strings variables are used for values that contain character strings. The only operator that can be used on string is concatenation denoted by the sign (.) period.

$wrd1=”Hello World”;
$wrd2=”Good day”;
print $wrd1.”".$wrd2

You can count the nos. of string with the function strlen().

Print strlen(”HelloWorld and GoodDay”);

to be continued…

image source: www.php-editors.com

Here are some of the basic things to be in mind while coding your dynamic web pages using PHP.

I. PHP basic syntax

PHP is a script that is place inside a HTML document that’s why you need to put the basic codes of HTML such as and .
PHP is open with the (?)question mark followed by “PHP” and closed with a (?) question mark.

II. Displaying in PHP

In order to display a text in PHP you need to use the keyword ECHO or PRINT. all code line ends with a semicolon.

To be continued…

image source: www.23hq.com

by: mheo soriano

This is a simple code that exports mysql database data to csv (delimated) data.

//a small class for database connectivity
class database {
private $db_handle;
private $user_name;
private $password;
private $data_base;
private $host_name;
private $sql;
private $results;
function __construct($host = “localhost”, $user, $passwd) {
$this->db_handle = mysql_connect($host, $user, $passwd);
}
function dbSelect($db) {
$this->data_base = $db;
if (!mysql_select_db($this->data_base, $this->db_handle)) {
error_log(mysql_error(), 3, “/phplog.err”);
die(”Error connecting to Database”);
}
}
function executeSql($sql_stmt) {
$this->sql = $sql_stmt;
$this->result = mysql_query($this->sql);
}
function returnResults() {
return $this->result;
}
}
//database variables
$host = “localhost”;
$user = “root”;
$passwd = “”;
$db = “bg_db”;
$sql = “SELECT * FROM table ORDER BY id”; // a query to fetch records from database
$dbObject = new database($host, $user, $passwd);
$dbObject->dbSelect($db);
$dbObject->executeSql($sql);
$res = $dbObject->returnResults(); // result reasource
$newFileName = “emp_names.csv”; //file name that you want to create
$fpWrite = fopen($newFileName, “w”); // open file as writable
$nameStr = “”;
$rows = mysql_fetch_assoc($res); // fetching associate records
$sStr = “”;
//first store the fields name as header of csv in $sStr
foreach($rows as $key=>$val) {
$sStr .= $key.”,”;
}
//then store all records
do {
$sStr .= “– —–\n”; //to seprate every record
foreach($rows as $key=>$row) {
$sStr .= $row.”,”;
}
}while($rows = mysql_fetch_assoc($res));
$sStrExp = explode(”– —–”, $sStr);//separate every record
foreach($sStrExp as $val) {
$sStr2 .= rtrim($val, “,”);
}
echo $sStr2;
fwrite($fpWrite, $sStr2); //now write to csv file
fclose($fpWrite);//close file
?>