PHP 程式設計必知重點

class DB {
    function DB() {
        $this->host = "localhost"; // your host
        $this->db = "myDatabase"; // your database
        $this->user = "root"; // your username
        $this->pass = "mysql"; // your password

        $this->link = mysql_connect($this->host, $this->user,  
$this->pass);
        mysql_select_db($this->db);
    }
}

// calls it to action
$db = new $DB;

$result = mysql_query("SELECT * FROM table ORDER BY id ASC LIMIT 0,10");

function magicQuotes($post) {

	if (get_magic_quotes_gpc()) {
		if (is_array($post) {
			return array_map('stripslashes',$post);
		} else {
			return stripslashes($post);
		}
	} else {
		return; // magic quotes are not ON so we do nothing
	}

}

function escapeString($post) {

	if (phpversion() >= '4.3.0') {
		return array_map('mysql_real_escape_string',$post);
	} else {
		return array_map('mysql_escape_string',$post);		
	}

}

error_reporting(E_ALL);

print_r($result); exit;

if ($rs['prefix'] == 1) {
	$prfx = 'Mrs. ';
} elseif ($rs['prefix'] == 2) {
	$prfx = 'Ms. ';
} else {
	$prfx = 'Mr. ';
}

echo $prfx.$rs['name'].' '.$rs['last_name'];

function makePrefix($prefix='')
{
	if (!$prefix) return '';
	if ($prefix == 1) return 'Mrs. ';
	if ($prefix == 2) return 'Ms. ';
	if ($prefix == 3) return 'Mr. ';
}

echo makePrefix($rs['prefix']) . $rs['name'] . ' ' . $rs['last_name'];

$var = $value; // ok
$var = "$value"; // ok, but double quotes are not necessary
$var = '$value'; // will not work (single quotes will not allow parsing)

('.' the period adds/connects variables, functions, etc. together. 
Oftentimes programmers will leave spaces around the ' . ' to make 
things easier to read.)

$var = 'This is the ' . $value . ' of things.'; // ok - preferred 
technique
$var = "This is the $value of things."; // ok, but harder to read/debug
$var = 'This is the $value of things.'; // will not parse $value
$var = This is the $value of things.; // error

$var = $array['name']; // ok, generally the preferred technique
$var = $array["name"]; // ok, but why use double quotes if they are not 
necessary?
$var = "$array[name]"; // ok, but harder to read/debug - poor coding 
style

$var = 'Name: ' . $array['name']; // ok - preferred technique
$var = "Name: $array[name]"; // ok, but harder to read/debug - poor 
coding style
$var = "Name: $array["name"]"; // error
$var = "Name: $array['name']"; // error

exampleFunction($value); // ok
exampleFunction("$value"); // ok, but double quotes are not necessary
exampleFunction('$value'); // will not parse $value

$line = $result['name'] . ' ' . $result['last_name']; // ok - easy to 
read/debug
$line = $result["name"] . ' ' . $result["last_name"]; // ok, but why 
use double quotes if they are not necessary?
$line = "$result[name] $result[last_name]"; // ok - but much harder to 
read/debug - poor coding style

$line = $result['name'] . ' ' . doSomething($result['last_name']); // 
ok - preferred method (using a function)

if (empty($_POST['action'])) {
	$action = 'default';
} else {
	$action = $_POST['action'];
}

$action = (empty($_POST['action'])) ? 'default' : $_POST['action'];

function safeQuery($query='')
{
	global $db;
	if (!$query) return false;	
	return mysql_query($query, $db->link);
}

// returns an array of records
function fetchArray($query='')
{
	if ($result = safeQuery($query)) {
		if (mysql_num_rows($result) > 0) {
			while ($arr = mysql_fetch_assoc($result)) $rows[] = $arr;
			return $rows;
		}
	}
	return false;
}

// returns a single record
function fetchRecord($query='')
{	
	if ($row = safeQuery($query)) {
		if (mysql_num_rows($row) > 0) {
			return mysql_fetch_assoc($row);
		}
	}
	return false;
}

$results = fetchArray("SELECT id,field1 FROM records");

// sample output results
if (!$results) {
	echo 'No results.';
} else {
	// loop the data
	foreach ($results as $result) {
		echo $result['id'] . ' ' . $result['field1'];
	}
}