PHP Programming With Mysql

PHP Programming With Mysql

PHP is a server-side scripting language used to create dynamic Web pages. It can be embedded into HTML and other formats, but it's most commonly used with the HTML .

PHP scripts execute on the server before being sent to the client. The script has access to all of the resources on that server, including files stored in its filesystem.

PHP scripts are often referred to as "scriptlets" because they don't run all at one time; they're executed when called upon by another program or scriptlet (another PHP program).

The main advantage of using PHP instead of JavaScript (a language common in web browser-based applications) is that PHP runs on the server side so you can use it for things like creating database queries and processing data from those queries without having to send any information back over a network connection -- your users will never even know what you're doing behind their backs!

What Is PHP?

PHP is a scripting language. It's a server-side language, which means it runs on the server computer that hosts your website and responds to requests from your web browser. PHP can also be used in command line mode; this allows you to run scripts without needing a web server running in the background.

PHP is free and open source. This means no licensing fees are required when using the language, and that anyone can modify it and contribute back changes for everyone else to use!

PHP has been around since 1994, making it one of the oldest programming languages on our list (it's older than JavaScript). Because of its age, PHP doesn't have some newer features that other popular programming languages do—like classes or namespaces—but these aren't necessary for basic web development projects anyway! The fact that PHP is supported by many hosting providers makes it much easier for beginners who want their first experience developing websites with minimal setup requirements."

The Structure of a PHP Script

When you write a PHP script, there are several ways in which you can include it into your HTML. In the following example code, the PHP script is embedded between tags:

More on Variables and Strings

We've already learned that variables are containers for data that can be changed, but what exactly do we mean by "variable"?

A variable is a container for a value that may change. You can think of it like a box with an arbitrary name and content, which can be changed later on by assigning new values to the boxes. Variables must be declared before you can use them in your PHP code. The following lines show examples of declaring scalar and array variables:

$name = 'John'; // Declares $name as type string

$age = 27; // Declares $age as type integer

Comments

Comments in PHP are very important. They can be used to document code, disable code temporarily, and disable code permanently. Comments are ignored by the PHP interpreter and do not affect the outcome of your program.

Operators and Expressions

Operators are used in PHP to perform operations on variables. For example, if you wanted to compare the values of two variables, you would use an operator. There are many different types of operators and they can be grouped into categories based on their function: arithmetic operators, relational operators and logical (or conditional) operators.

Strings and String Manipulation

Strings are a basic element of programming and PHP is no exception. In the language, strings are surrounded by single or double quotes. To make sure that you don't accidentally type an opening quote when you mean to type a closing quote, it's helpful to use a visual marker like this: ``this is a string``

The difference between single-quoted and double-quoted strings is that single-quoted strings only allow one word while double-quoted strings allow multiple words. For example, if you wanted to write "This is how I feel," then you would use this code:

//single quoted string

echo 'I am happy'; //prints out "I am happy" (no newline)

//double quoted string - multiple words allowed

echo "I'm so excited about today"; //prints out "I'm so excited about today" (with newline) You can also concatenate two or more strings together using the plus sign (+). This will add them end-to-end into one big long string. Keep in mind that each word must be surrounded by quotation marks! Let's take an example: echo 'This' + 'is my first time.'; //prints out "Thisismyfirsttime." If there are any spaces between words, they will be removed from the outputted result when added together with other characters—so don't worry too much if things look weird at first glance!

Arrays

All arrays start with the array keyword and are enclosed in parentheses. Arrays can be declared as associative or numeric.

Numeric arrays are used to store values of a particular type, such as integers or floats. You can initialize an empty numeric array by separating each element with commas:

$numbers = [1,2,3] // nope! This is not a valid PHP syntax! $numbers = [0]; $numbers[] = 1; $numbers[] = 2; $numbers[] = 3; // valid syntax

Looping Constructs

Looping constructs allow you to repeat a block of code until a particular condition is met. Loops are crucial for extracting information from large data sets and performing repetitive tasks.

There are four different types of looping constructs: while, do-while, for and foreach.

The while statement begins with the keyword while followed by an expression that evaluates to true or false . It then executes the body of code as long as this expression is true . The do-while statement behaves similarly but it also ensures that at least one iteration of its body occurs before checking whether it should continue iterating.

For example: $i = 1; while($i < 5) { echo $i . " "; $i++; } would output 1 2 3 4 5 .

A for statement is similar but it allows you to specify an initialization value ($i = 1), an increment (++$i), and/or a final result ($j = 5). In this example: $j = 0; for($k=1; $k <= 10; ++$j) { echo "$j"; } would output 1 2 3 4 5 6 7 8 9 10 , incrementing each value by one until reaching 10 in the final iteration where we reset our variables back down again so they can start counting over again from zero (0). Foreach loops provide another way to iterate over arrays or other collections without having to explicitly define each individual element in your array using indexes or keys respectively - instead all you need do is loop through every item within something like [1...10]* once per iteration*.

Form Processing by Using PHP

PHP provides four functions to handle form processing.

• $_POST and $_GET: These variables are used to retrieve information entered by the user in HTML forms. $_POST is used to store values that were sent when a form was submitted by the user, while $_GET stores values that were sent automatically when a page was first loaded. For example, if you have an HTML form containing two fields named title and text, when you submit this form using your browser it will send two pieces of data to PHP via HTTP protocol: name=title&email=my@email.com (the name and email fields) or name=John&surname=Smith (the name field only).

• Cookies: Cookies can be used for storing information related to a particular session or user session on your website so that each time the user returns there will be no need for him/her re-enter some required data such as username and password etc., which makes things simple on their part because all this information will be available in their browsers’ cache memory which they can access later whenever they want so long as they don't delete it manually from there before exiting their browsers altogether! Cookies are stored locally meaning only inside computer where website owner has installed them onto his machine but not outside like other types mentioned below...

Integrating PHP with Databases, Such as MySQL and SQL Server

You can use PHP to create dynamic Web pages. A dynamic Web page is one that is created on the fly by the server and sent back to a Web browser for display. The most common way of doing this is with HTML forms. When you type in your name, address and telephone number into an online form, you are telling the server software which information to send back to your browser as part of a response string.

The HTML code in this response string tells your browser how to display each item that came from the form: whether it should be shown as text, displayed as an image or perhaps turned into an e-mail message inside another window on your screen (a pop-up). This process allows you to fill out a form with multiple items without reloading the page every time you add something new—and it saves bandwidth because only those items within the response string change when data changes instead of all page contents being reloaded over again each time some new info gets entered into any given field!

Sessions in PHP and Database Interaction, Part 1

In this section, we will cover:

• What is a session?

• How to use sessions in PHP.

• How to use sessions with a database.

In the next chapter, we'll cover:

• How to store data in a session and retrieve it later.

We are also going to introduce the concept of saving user preferences (e.g., fonts or colors they like) and storing them so that they can be used on subsequent visits without having to re-enter them every time someone logs in.

This book provides all you need to know to start developing dynamic Web sites.

This book provides all you need to know to start developing dynamic Web sites. It explains how PHP works, how to install it on your computer, and the basics of writing a few simple scripts. You'll be able to use PHP for both simple and complex applications, such as a guestbook or message board system. You'll also learn how PHP interacts with MySQL databases so that you can create database-driven web applications with ease.

PHP is a server-side scripting language designed specifically for web development; it's an open source language that runs on almost any platform imaginable—even your smartphone! With this book as your guide, you'll quickly master everything from basic syntax and variables all the way up through object-oriented programming techniques like inheritance and polymorphism (the ability for one object type to take on multiple forms). Once you've got those down pat, we'll show you how they apply directly within the context of building real-world applications using major frameworks like Zend Framework 2 (ZF2) or Symfony 2.*