PHP started out as a small open source project that evolved as
more and more people found out how usefulit was. Rasmus Lerdorf
unleashed the first version of PHP way back in 1994. PHP is a
recursive acronym for PHP! Hyperte"t Preprocessor. PHP is a server
side scriptin# lan#ua#e that is embedded in H$%L. &t is used to
mana#e dynamiccontent' databases' session trackin#' even build
entire e(commerce sites. &t is inte#rated with a number of
popular databases' includin# %y)*L' Post#re)*L' +racle'
)ybase'&nformi"' and %icrosoft )*L )erver. PHP is pleasin#ly
,ippy in its e"ecution' especially when compiled as an -pache
module on the .ni"side. $he %y)*L server' once started' e"ecutes
even very comple" /ueries with hu#e result sets inrecord(settin#
time. PHP supports a lar#e number of major protocols such as P+P0'
&%-P' and L1-P. PHP4 added supportfor 2avaanddistributedobject
architectures34+%and4+R5-6' makin#n(tier development apossibility
for the first time. PHP is for#ivin#! PHP lan#ua#e tries to be as
for#ivin# as possible. PHP )ynta" is 4(Like.Common uses of PHP: PHP
performs system functions' i.e. from files on a system it can
create' open' read' write' andclose them. PHP can handle forms'
i.e. #ather data from files' save data to a file' thru email you
can send data'return data to the user. 7ou add' delete' modify
elements within your database thru PHP. -ccess cookies variables
and set cookies. .sin# PHP' you can restrict users to access some
pa#es of your website. &t can encrypt data.Characteristics of
PHP8ive important characteristics make PHP9s practical nature
possible! )implicity :fficiency )ecurity 8le"ibility
8amiliarity"Hello World" Script in PHP:$o #et a feel for PHP' first
start with simple PHP scripts. )ince Hello' ;orld< is an
essential e"ample' firstwe will create a friendly little Hello'
;orld< script.-s mentioned earlier' PHP is embedded in H$%L.
$hat means that in amon#st your normal H$%L 3or =H$%Lif you9re
cuttin#(ed#e6 you9ll have PHP statements like this!
Hello World
&t will produce followin# result!Hello, World!&f you
e"amine the H$%L output of the above e"ample' you9ll notice that
the PHP code is not present in thefile sent from the server to your
;eb browser. -ll of the PHP present in the ;eb pa#e is processed
andstripped from the pa#e> the only thin# returned to the client
from the ;eb server is pure H$%L output.-ll PHP code must be
included inside one of the three special markup ta#s ate are
reco#nised by the PHPParser.
PHP code goes here %ost common ta# is the ?@php...@A and we will
also use same ta# in our tutorial.8rom the ne"t chapter we will
start with PHP :nvironment )etup on your machine and then we will
di# outalmost all concepts related to PHP to make you comfortable
with the PHP lan#ua#e.&n order to develop and run PHP ;eb pa#es
three vital components need to be installed on your computersystem.
Web Server - PHP will work with virtually all ;eb )erver software'
includin# %icrosoft9s &nternet&nformation)erver
3&&)6 but thenmost
oftenusedisfreelyavailble-pache)erver.1ownload-pache for free here!
http!BBhttpd.apache.or#Bdownload.c#i Database -PHPwill work with
virtuallyalldatabasesoftware'includin#+racle and )ybase butmost
commonly used is freely available %y)*L database. 1ownload %y)*L
for free here!http!BBwww.mys/l.comBdownloadsBinde".html PHP Parser
-&n order to process PHP script instructions a parser must be
installed to #enerateH$%L output that can be sent to the ;eb
5rowser. $his tutorial will #uide you how to install PHPparser on
your computer.PHP Parser Installation:5efore you proceed it is
important to make sure that you have proper environment setup on
your machineto develop your web pro#rams usin# PHP.$ype the
followin# address into your browser9s address
bo".http//!"#$%$%$!/in&o$php&f this displays a pa#e showin#
your PHP installation related information then it means you have
PHP and;ebserver installed properly. +therwise you have to follow
#iven procedure to install PHP on your computer.$his section will
#uide you to install and confi#ure PHP over the followin# four
platforms! PHP &nstallation on Linu" or .ni" with -pache PHP
&nstallation on %ac +) = with -pache PHP &nstallation on
;indows C$BDEEEB=P with &&) PHP &nstallation on ;indows
C$BDEEEB=P with -pacheApache Confguration:&f you are usin#
-pache as a ;eb )erver then this section will #uide you to edit
-pache 4onfi#uration 8iles.2ust 4heck it here ! PHP 4onfi#uration
in -pache )erverPHP.INI File Confguration:$he PHP confi#uration
file' php.ini' is the final and most immediate way to affect PHP9s
functionality.2ust 4heck it here! PHP.&C& 8ile
4onfi#urationWindows IIS Confguration:$o confi#ure &&) on
your ;indows machine you can refer your &&) Reference
%anual shipped alon# with &&).$hischapterwill
#iveyouanideaof verybasicsynta"of PHPandveryimportant tomakeyour
PHPfoundation stron#.Escaping to
PHP:$hePHPparsin#en#ineneedsawaytodifferentiatePHPcodefromotherelementsinthepa#e.
$hemechanism for doin# so is known as 9escapin# to PHP.9 $here are
four ways to do this!Canonical PHP tags:$he most universally
effective PHP ta# style is!
&f you use this style' you can be positive that your ta#s
will always be correctly interpreted.Short-open (SGML-style)
tags:)hort or short(open ta#s look like this!
)hort ta#s are' as one mi#ht e"pect' the shortest option 7ou
must do one of two thin#s to enable PHP toreco#ni,e the ta#s!
4hoose the ((enable(short(ta#s confi#uration option when you9re
buildin# PHP. )et the shortFopenFta# settin# in your php.ini file
to on. $his option must be disabled to parse =%Lwith PHP because
the same synta" is used for =%L ta#s.ASP-style tags:-)P(style ta#s
mimic the ta#s used by -ctive )erver Pa#es to delineate code
blocks. -)P(style ta#s look likethis!
$o use -)P(style ta#s' you will need to set the confi#uration
option in your php.ini file.HML script tags:H$%L script ta#s look
like this!$$$Commenting PHP Code:-commentistheportionof
apro#ramthate"istsonlyforthehumanreaderandstrippedoutbeforedisplayin#
the pro#rams result. $here are two commentin# formats in
PHP!Single-line co!!ents: $hey are #enerally used for short
e"planations or notes relevant to the local code.Here are the
e"amples of sin#le line comments.
M"lti-linesco!!ents:$heyare#enerallyusedtoprovidepseudocodeal#orithmsandmoredetailede"planations
when necessary. $he multiline style of commentin# is the same as in
4. Here are the e"ampleof multi lines comments.
&t will produce followin# result!
WhatBs .or 0innerhttp//menu$e,ample$com/7hoose -hat to eat
tonight$
