Php programming in Constants and Variables CRUD Operations

Constants can’t override once declared

Only Upper Case Characters

No Dollar Sign!

<?php 
	/* *
	 * Constants
	 *  - Constants can't override once declared
	 *  - Only Upper Case Characters
	 *  - No Dollar Sign
	 */

	define('VARR', "Hello World");
	
	define('SOME_VAR', 150);

	echo VARR;

	echo "<br>";

	echo SOME_VAR;


	define('HELLO', "Hello World");

	echo HELLO;

	define('HELLO', 123);

	echo HELLO;
 ?>

Variables CRUD Operations in PHP

<?php 
	/* *
	 * Variables CRUD Operations
	 */

	// Create
	$var = 50;

	// Read
	echo $var;

	// Update
	$var = 80;

	// Read Again
	echo $var;

	// Delete
	unset($var);

	// Read Again and You will get Undefine Variable Error
	echo $var;
 ?>

Naming Rules, No Space, No Special Characters ( Shift + 1 to 0), / \ ? . > < = ~ ` ' " { ( [ | ; : ,

Can’t be a Number on First Character

Case-sensitive

<?php

	/**
	* Naming Rules
	* - No Space
	* - No Special Characters ( Shift + 1 to 0)
	* - / \ ? . > < = ~ ` ' " { ( [ | ; : , 
	* - Can't be a Number on First Character
	* - Case-sensitive
	*/

	/* 
	
        / - Slash
	\ - Backslash
	? - Question Mark
	> - Greater Than
	< - Less Than
	= - is equal to
	~ - Tilde symbol
	` - Back Quote or Back Tip
	' - Single Quote
	" - Double Quote
	{} - Curly Brackets
	() - Parentheses or Round Backets
	[] - Square Brackets
	| - Pipe Symbol
	; - Semi-colon
	: - Colon
	& - Ampersand
	* - Asterisk
	# - Hash

	*/

	$var = 10;

	$var1 = 50;

	$v2ar = "Hello World";

	$var_two = 90;

	$va_r = 40;

	$_var_ = 120;

	$vAR = 150;

	$Var = 250;

	$VAR = 550;

	$vAr = 510;

	// You can Override Variables by Redeclaring
	
	$vAr = 300;
	echo $vAr;
	
 ?>

Thats the PHP programming basic of our future.

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