PHP Basics - SkillBakery Studios


Post Top Ad

Post Top Ad

Monday, June 15, 2020

PHP Basics

Welcome to one of the most widely used programming languages used to develop web applications.

“PHP: hypertext preprocessor “programming language which allows web developers to create dynamic content that interacts with the databases.
PHP uses simple code, anyone with the basic programming knowledge can learn and work on PHP. It is a server-side scripting language used to develop dynamic web pages
PHP can integrate with many databases like MySQL, Sybase, ORACLE, Microsoft SQL Server.

This blog post will help you understand the basics of PHP

First, see what can we do with PHP?

·       In PHP we can restrict the user access to some web pages as per demand.
·       PHP can encrypt data
·       In PHP we can easily add, delete and modify data with the database
·       PHP can set cookies
·       It allows execution of inline code
·       It’s easy to scale up 

PHP Installation Prerequisites

To start developing with PHP all we need is the three most important component installed.

Web server – PHP can work virtually with all webserver including Microsoft IIS.

Database – PHP can work with different databases but commonly uses MySQL.

PHP parser – As PHP is a server-side scripting language so to process the instructions a parser must be installed to generate HTML output which is then sent to the server.


To install PHP follow the given video link in order to know step by step instructions

Why to Use PHP?

                 PHP is easy to understand.
                 It’s an open-source language.
                 It’s cost-effective for the organization.
                 PHP is a server-side scripting language which means you only have to install it on
          the server and clients can easily use the resources without having installed.
   PHP is a cross-platform that means you can deploy your application on 
   different operating systems such as Linux, Mac OS, windows, etc.

     File Extension in PHP 

       To identify any PHP file we have saved our file with .php extension.
       PHP can easily work with HTML and is embedded into the HTML code.
       For e.g.

     <PHP CODE>

      Server interprets the PHP code and results as HTML code to the web browsers. 
      Server identifies the PHP code within the HTML code with the PHP tags. 
      PHP is a case sensitive language.PHP statements end with a semicolon(;)
      PHP scripts are executed on the server.

    PHP Variables

       PHP variables are used to hold values or expressions.
       A variable can have a short name, like x, or a more descriptive name, like carName.
       Rules for PHP variable names:

    • Variables in PHP starts with a $ sign, followed by the name of the variable
    • The variable name must begin with a letter or the underscore character
    • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
    • A variable name should not contain spaces
    • Variable names are case sensitive (y and Y are two different variables)

    Creating (Declaring) PHP Variables

        PHP has no command for declaring a variable.
        A variable is created the moment you first assign a value to it:


      After the execution of the statement above, the variable myCar will hold the value Volvo.
      Tip: If you want to create a variable without assigning it a value
      Then you assign it the value of null.
      Let's create a variable containing a string, and a variable containing a number:

            $txt="Hello World!";

       Note: When you assign a text value to a variable put quotes around the value.

    PHP is a Loosely Typed Language

      In PHP, the variable does not need to be declared before adding value to it.

    In the example above, notice that we did not have to tell PHP which data type the variable is.PHP automatically converts the variable to the correct data type, depending on its  value. In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it.

    PHP Variable Scope

      The scope of a variable is the portion of the script in which the variable can be referenced.
      PHP has four different variable scopes:
    • local
    • global
    • static
    • parameter
    Local Scope

      A variable declared within a PHP function is local and can only be accessed within
      that function. (the variable has local scope):
           $a = 5; // global scope

           function myTest()
           echo $a; // local scope


       The script above will not produce any output because the echo statement refers to the local scope variable $a, which has not been assigned a value within this scope.You can have local variables with the same name in different functions because local variables are only recognized by the function in which they are declared. Local variables are deleted as soon as the function is completed.

    Global Scope

       Global scope refers to any variable that is defined outside of any function.
       Global variables can be accessed from any part of the script that is not inside a function.
       To access a global variable from within a function, use the global keyword:

         $a = 5;
         $b = 10;

         function myTest()
         global $a, $b;
         $b = $a + $b;

          echo $b;

       The script above will output 15.

       PHP also stores all global variables in an array called $GLOBALS[index]. Its index is 
       the name of the variable. This array is also accessible from within functions and can 
       be used to update global variables directly.
       The example above can be rewritten as this:

       $a = 5;
       $b = 10;

       function myTest()
       $GLOBALS['b'] = $GLOBALS['a'] + $GLOBALS['b'];

       echo $b;

    Static Scope

      When a function is completed, all of its variables are normally deleted. 
      However, sometimes you want a local variable to not be deleted.
      To do this, use the static the keyword when you first declare the variable:
      static $rememberMe;
      Then, each time the function is called, that variable will still have the information 
      it contained from the last time, the function was called.

      Note: The variable is still local to the function.


      A parameter is a local variable whose value is passed to the function by the calling code.
      Parameters are declared in a parameter list as part of the function declaration:

      function myTest($para1,$para2,...)
      // function code
      Parameters are also called arguments. We will discuss them in more detail when we 
      talk about functions.

    PHP String Variables

    String Variables in PHP

     String variables are used for values that contain characters.

     In this blog post, we are going to look at the most common functions and operators used 
     to manipulate strings in PHP. After we create a string we can manipulate it. A string can be   used directly in a function or it can be stored in a variable.

     Below, the PHP script assigns the text "Hello World" to a string variable called $txt:

      $txt="Hello World";
      echo $txt;
    Creating your first PHP Applications

    Below, we have an example of a simple PHP script that sends the text "Hello World" back to the browser:


      echo "Hello World";


    Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another.

    There are two basic statements to output text with PHP: echo and print.
    In the example above we have used the echo statement to output the text "Hello World".

    No comments:

    Post a Comment

    Post Top Ad