PHP Learning--Part 1

Today, i learn PHP language. I know a lot about C/C++, Delphi, Java but nothing about web programming(such as PHP). So now i will self-study PHP. I know it is difficult when you are starting learning new language. But when you have base knowledge. It will be easier.
First glance at PHP:

PHP, which stands for "PHP: Hypertext Preprocessor" is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. Its syntax draws upon C, Java, and Perl, and is easy to learn. The main goal of the language is to allow web developers to write dynamically generated web pages quickly, but you can do much more with PHP.

That is definition in PHP.net. But in my opinion, in short way, PHP just a server side script run in server side. That's all.

Now i want to know the key feature of PHP. Let's start by study:
1. Server-side scripting:

This is the most traditional and main target field for PHP. You need three things to make this work. The PHP parser (CGI or server module), a web server and a web browser. You need to run the web server, with a connected PHP installation. You can access the PHP program output with a web browser, viewing the PHP page through the server. All these can run on your home machine if you are just experimenting with PHP programming

2.Command line scripting:

You can make a PHP script to run it without any server or browser. You only need the PHP parser to use it this way. This type of usage is ideal for scripts regularly executed using cron (on *nix or Linux) or Task Scheduler (on Windows). These scripts can also be used for simple text processing tasks
Note: It is like batch processing or Shell Programming. Good for system task such as make server log, backup....

3.Writing desktop applications. PHP is probably not the very best language to create a desktop application with a graphical user interface, but if you know PHP very well, and would like to use some advanced PHP features in your client-side applications you can also use PHP-GTK to write such programs. You also have the ability to write cross-platform applications this way. PHP-GTK is an extension to PHP, not available in the main distribution. If you are interested in PHP-GTK, visit http://gtk.php.net/.
Note: So cool. I do not know about this. Maybe i tried. ^_^ I only know that PHP is for Web development.

4. Database support:
Adabas D InterBase PostgreSQL
dBase FrontBase SQLite
Empress mSQL Solid
FilePro (read-only) Direct MS-SQL Sybase
Hyperwave MySQL Velocis
IBM DB2 ODBC Unix dbm
Informix Oracle (OCI7 and OCI8)
Ingres Ovrimos

We only need some key database server like MySQL, Oracle, Innobase, DB2, SQL Server(not see in the list. I will find the way to work around.).