Difference between revisions of "PHP"

Revision as of 18:06, August 10, 2010

PHP is a server-side scripting language for creating interactive web pages. The acronym PHP derives from Personal Home Page, but is now defined as "PHP: Hypertext Pre-Processor" (it means "something to handle data before it becomes HTML" ^[1] ). Unlike HTML, JavaScript and others, PHP is a Server-Side scripting language. It most always is processed into HTML for use in a web page.

PHP is one of the most popular scripting languages in the Open Source world, which is often used together with Apache on Linux or on other paid platforms such as Microsoft IIS on Windows.

The PHP syntax is very similar to Perl and C. ^[2]

PHP is an interpreted language (like Perl) and not a compiled one (like Java or C).

Strings

Strings can be placed in single quotes or double quotes; this differs from Java, where single quotes are used only to enclose one single character rather than a string.

Important note:

• single quoted strings don't recognize special character codes like \n ^[3]

Concatenation

The string concatenation operator is the period (or full stop). This is a major difference from many other programming languages, which use a plus sign or ampersand.

Example:

 $first = "car";
 $second = "nation";
 $product= $first . $second;

 // Equivalent to:
 $product= "carnation"

PHP recognizes variable names within strings, which are enclosed in double quotes. Since all variables begin with a dollar sign, it is easy to embed one string inside another. This is the preferred way to create HTML output.

For example:

   $first = "John";
   $middle = "Quincy"
   $last = "Adams";
   
   // Show full name, in bold format
   echo "<B>$first $middle $last</B>";

This outputs "<B>John Quincy Adams</B>" to the HTML page.

Databases

PHP is compatible with multiple databases, MySQL being the most popular. They go together so well that it's tempting to think of PHP as primarily middleware to link MySQL on the back end to HTML on the front end.

Overall, PHP is compatible with:

• MySQL
• PostgreSQL
• MS-SQL 2000
• Oracle
• SQLite

and many others.

Books

• How to Do Everything with PHP & MySQL, Vikram Vaswani (McGraw-Hill, 2005)

External links

• PHP Tutorial - W3 Schools
• PHP.net - Offical PHP Website.

References

1. ↑ HTMLite PHP Tutorial
2. ↑ PHP Tutorial from W3Schools
3. ↑ Advanced PHP from Sitepoint