Senior PHP Programmer

$$var sets the value of $var as a variable.

$day='monday';

$$day='first day of week';

echo $monday; //outputs 'first day of week'

They are trying to gauge your understanding of how class auto loading works. Review the "autoload" and "spl_autoload_register" function (note:you should use the later). The autoload function basically triggers a function when a class is instantiated, you can put whatever logic you like in it but generally you want to include the class file based on some sort of naming convention.

_FILE_ − The full path and filename of the file. If used inside an include,the name of the included file is returned. Since PHP 4.0.2, _FILE_ always contains an absolute path whereas in older versions it contained relative path under some circumstances.

To define a constant you have to use define() function and to retrieve the value of a constant, you have to simply specifying its name. Unlike with variables, you do not need to have a constant with a $.

require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.

To send email using PHP, you use the mail() function.This mail() function accepts 5 parameters as follows (the last 2 are optional). You need webserver, you can't send email from localhost.

eg : mail($to,$subject,$message,$headers);

This function is used to determine if a variable is set and is not NULL

Setcookie("sample", "ram", time()+3600);

Split function splits string into array by regular expression. Explode splits a string into array by string.

SQL injection is a malicious code injection technique.It exploiting SQL vulnerabilities in Web applications

"method" attribute determines how to send the form-data into the server.There are two methods, get and post. The default method is get.This sends the form information by appending it on the URL.Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.

It is used for sort an array by key in reverse order.

The header() function sends a raw HTTP header to a client browser. Remember that this function must be called before sending the actual out put. For example, You do not print any HTML element before using this function.

Create session : session_start();

Set value into session : $_SESSION['USER_ID']=1;

Remove data from a session : unset($_SESSION['USER_ID'];

We can include a file using "include() " or "require()" function with file path as its parameter.

There are a number, but the big ones people are looking for are:

☛ PHP 5.0 realised the object model (AKA OOP).

☛ 5.1 added PDO - for accessing databases.

☛ 5.3 - added namespace support and late static bindings.

Design patterns are simply commonly used techniques within your code, they often are implemented in different ways so they can be a bit tricky to grasp without writing them yourself. If you are unfamiliar with them I would start by learning the Singleton Pattern and the Strategy Pattern.