Wilamowski B.M., Irwin J.D. The Industrial Electronics Handbook. Second Edition: Industrial Communication Systems

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Development of Interactive Web Pages 62-3

You. can. download. the. latest. WAMP. server. soware. from. the. following. Web. site:. http://www.

wampserver.com/en/download.php.

Aer

.you.down

load

.the.pack

age,

.doub

.clic

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utable

.le.and.choo

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ination

.path.(by.

defa

ult

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amp)

.for.the.sowa

.to.be.inst

alled

.on.your.comp

uter.

.Foll

.the.inst

ructions

.prov

ided

.on.

the.Web.site.and.ever

ything

.will.be.easi

.inst

alled.

.Once.the.sowa

.is.inst

alled,

.you.can.add.othe

rele

ases

.of.PHP,.MySQ

.and.Apac

.by.down

.them.from.thei

.Web.site

.and.you.will.be.able.

to.easi

.swit

.betw

een

.rele

ases.

.Aer.Wamp

Server

.is.inst

alled,

.a.tray.icon.to.mana

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show

.at.righ

.end.of.the.task

bar.

.By.le.clic

king

.on.the.icon

.you.will.see.a.menu.to.mana

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sett

ings.

.Once.you.inst

all

.Wamp

Server,

.a.“www

”

.dire

ctory

.is.crea

ted

.(c:\

wamp\www)

.and.you.will.see.an.

“ind

ex.php”

.le.in.it..Do.not.modi

.this.le.beca

use

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gnizes

.it.as.its.defa

ult

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page.

Creat

.a.dire

ctory

.insi

.it.and.stor

.all.your.PHP.or.HTML.les.in.it..To.crea

.a.data

base,

.you.can.fol-

.the.trad

itional

.meth

.by.open

ing

.the.SQL.cons

ole

.and.typi

.the.comm

ands

.that.will.crea

.your.

data

base.

.Anot

her

.way.of.crea

ting

.data

bases

.and.hand

ling

.the.admi

nistration

.of.one.or.more.MySQ

serv

ers

.is.thro

ugh

.phpM

yAdmin.

.PhpM

yAdmin

.is.an.open

-source

.tool.inte

nded

.to.crea

te,

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fy,

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dele

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bases,

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es,

.eld

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uting

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ements;

.or.mana

ging

.user

.and.perm

issions.

62.3 Introduction to PHP

A.PHP.script.can.be.easily.embedded.into.HTML.by.enclosing.the.code.with.PHP.tags,.<.?php.and.?.>,.

whic

.is.simi

lar

.to.HTM

.tag

.PHP.scr

ipting

.blo

.can.be.pla

ced

.any

where

.insi

.the.HTM

.doc

ument.

Example:

<html>

<body>

<?php

echo "Hello-this is my first PHP program\n";

/*echo statement display’s the text,Hello-this is my first PHP

program*/

</body>

</html>

Save.the.HTML.le.as.“test.php”.or.you.can.open.a.notepad,.copy.the.code,.and.save.it.as.“test.php.”

62.3.1 Variables

All.variables.in.PHP.start.with.the.“$”.sign.followed.by.the.name.of.the.variable..PHP.variables.are.used.to.

stor

.infor

mation

.and.can.be.used.wher

ever

.they.are.need

.in.the.scri

pt;

.like.text.stri

ngs,

.numb

ers,

.or.arra

ys.

Example:

<?php

$n=20.5;

$string="Welcome";

echo $string;

echo "<br>";

echo $n;

Output

.of.abo

.cod

.Wel

come

.20.

PHP

.als

.pro

vides

.“pr

int_r”

.fun

ction

.to.dis

play

.the.var

iable

.con

tents.

62-4 Industrial Communication Systems

62.3.2 Conditional Statements

Conditional.statements.such.as,.if,.if…else,.if…elseif…else,.switch.statements.are.used.to.perform.

di

erent

.act

ions

.bas

.on.di

erent

.dec

isions.

. a.. An.if.st

atement

.is.us

.to.ex

ecute

.th

.co

.on

.if.a.sp

ecied

.co

ndition

.is.tr

ue.

<?php

$np=1;

//if statement.

if ($np==5)

echo "Five";

. b.. An.if…

.else

.sta

tement

.is.use

.to.exe

cute

.som

.cod

.if.a.con

dition

.is.tru

.and.ano

ther

.cod

.if.

con

dition

.is.fal

se.

<?php

$p=10.55;

//if....else statement.

if ($p==3)

echo "Three";

else

echo "Try different number";

. c.. An.if

…elseif…else

.st

atement

.is.us

.to.se

lectively

.ex

ecute

.so

.co

.wh

.a.co

ndition

.is.tr

ue.

<?php

$i=10;

//if....elseif...else statement.

if ($n==1)

echo "One";

elseif ($i==2)

echo "Two";

if ($i==3)

echo "Three";

else

echo "Try different number";

. d.. A.sw

itch

.st

atement

.is.us

.to.ex

ecute

.on

.of.ma

.bl

ocks

.of.co

de.

Example:

//Switch Statement

<?php

$k=10;

switch ($k)

Development of Interactive Web Pages 62-5

{

case 1:

echo "One";

break;

case 2:

echo "Two";

break;

case 3:

echo "Three";

break;

default:

echo "Try between one and three";

}

62.3.3 Loops

Loops.are.used.to.repetitively.execute.a.block.of.code.until.or.when.a.specic.condition.is.true..Loops.

are.us

.to.pe

rform

.th

.sa

.ta

.ag

ain

.an

.ag

ain

.so.th

.we.do.no

.ha

.to.wr

ite

.se

veral,

.al

most

.eq

ual

sta

tements.

.PHP

.loo

.sta

tements

.suc

.as.whi

le,

.do…

.while,

.and.for.are.use

.di

erently

.dep

ending

.on.the.

con

dition.

Example:

//while statement.

<?php

$j=1;

//initializing variable

while ($j<=5){

echo $j;

$j++;

/*incrementing the value of j each time until the condition is not

met.*/

} ?>

Output of above code: 1 2 3 4 5

//do.....while statement

<?php

$k=1;

do {

$k++;

echo $k ;

}while ($k<=5);

Output: 2 3 4 5 6

//for loop

Syntax:

for (init; condition; increment){

code to be executed;

}

62-6 Industrial Communication Systems

Example:

<?php

for ($i=1; $i<=5; $i++) {

echo $i;

}

Output: 1 2 3 4 5

62.3.4 Functions

Functions.contain.scripts.that.are.called.to.execute.whenever.a.page.loads.or.is.called.from.anywhere.within.

a.page

. er

.are.aro

und

.700.bui

lt-in

.fun

ctions

.ava

ilable

.in.PHP.suc

.as.dat

.fun

ction,

.str

ing

.fun

ction,

.cal

endar

.fun

ction,

.arr

.fun

ctions,

.etc

.You.can.cre

ate

.you

.own.fun

ction

.to.ach

ieve

.a.spe

cic

.goa

Syntax:

function functionName(){

code to be executed;

}

Example

.1:.Wit

hout

.pa

rameters

<?php

function demo() {

//user defined function

$string1="Function string";

echo "function code is executed and displayed";

}

demo();

//calling a function, by using function name

Output: function code is executed and displayed

Exa

mple

.2:.Pa

rameters

.an

.re

turn

.va

lues

Parameters

.are.dec

lared

.insi

.the.par

enthesis.

.Par

ameters

.are.jus

.lik

.var

iables

.tha

.stor

.inf

orma-

tion

.wi

thin

.th

.fu

nction.

<?php

function add($x,$y){

//$x and $y are two parameters.

$t=$x+$y;

return $t;

/* function returns value $t using 'return'

statement.*/

}

echo "Sum is". add(1,5);

send values 1 and 5 to the function which in turn returns sum of

1 and 5 and final result is displayed by the echo statement.*/

Output: Sum is 6

62.3.5 Include Function

If.you.want.to.include.one.PHP.le.in.another.PHP.le,.include().or.require().functions.is.used.to.take.

the.co

ntent

.of.on

.l

.an

.in

clude

.it.in.th

.cu

rrent

.l

Development of Interactive Web Pages 62-7

Both.include().and.require().functions.serve.the.same.purpose.but.handle.errors.dierently..In.the.

case.of.the.incl

ude()

.func

tion,

.it.gene

rates

.a.warn

ing

.and.cont

inues

.to.exec

ute

.the.scri

.when

ever

.an.

erro

.occ

urs.

.Whe

reas

.req

uire()

.fun

ction

.gen

erates

.a.fat

.err

.and.ter

minates

.exe

cution.

.incl

ude()

.func

tion

.is.used.espe

cially

.if.a.bloc

.of.code

.are.reus

.on.mult

iple

.page

.For.exam

ple,

.hea

ders,

.foo

ters,

.adv

ertisements

.tha

.are.reu

sed

.on.di

erent

.pag

es.

Example:

<html>

<body>

<?php include("footer.php"); ?>

//include("filename.php")

</body>

</html>

62.3.6 $_GEt and $_POSt function

 e. built-in. $_GET. and. $_POST. functions. are. used. to. collect. values. from. an. HTML/PHP. form..

Howe

ver,

.both.func

tions

.hand

.info

rmation

.sent.from.a.form.in.die

rent

.ways

.Info

rmation

.sent.from.

a.form.using.the.GET.meth

.is.visib

.to.ever

yone

.(all.vari

ables

.are.disp

layed

.in.the.URL).and.is.lim-

ted

.to.send.up.to.100.char

acters.

.Wher

eas

.info

rmation

.sent.from.the.POST.meth

.is.not.visib

.to.

ever

yone

.(al

.var

iables

.are.not.dis

played

.in.the.URL

)

.and.the.cha

racters

.are.not.lim

ited.

Example:

Username: <input type="text" name="username" />

Password: <input type="text" name="pwd" />

</form>

When

.the.user.clic

.the.“sub

mit”

.butto

.the.form.send

.info

rmation

.atta

ched

.to.the.URL.to.the.

serv

er,

.whi

.loo

.lik

.htt

p://www.companyname.com/Login.php?Username=Tom&Password=123

And

.“Lo

gin.php”

.can.use.$_GE

.fun

ction

.to.col

lect

.dat

.fro

.the.for

<p> Your username: <?php echo $_GET["username"]; ?></p>

For

.the.sam

.exa

mple,

.rep

lace

.“ge

t”

.wit

.“po

st”

.und

.met

hod

.opti

.and.the.URL.wil

.loo

.lik

http://www.companyname.com/Login.php

And

.“Lo

gin.php”

.can.use.$_P

OST

.fun

ction

.to.col

lect

.dat

.fro

.the.for

<p> Your username: <?php echo $_POST["username"]; ?> </p>

.coll

ect

.data.that.is.sent.with.both.the.GET.and.POST.meth

ods,

.$_RE

QUEST

.func

tion

.can.be.used.i.e.

<p> Welcome <?php echo $_REQUEST["username"]; ?> </p>

62.4 MySQL

MySQL.is.a.database.system,.which.stores.data.in.the.form.of.tables..Each.table.is.identied.by.a.name.

and.con

tains

.row

.of.dat

.See.Tab

.62.

.for.an.exa

mple.

62-8 Industrial Communication Systems

Aer.installing.MySQL.server,.open.command.line.to.run.the.MySQL.client.program..To.connect.to.

your.MyS

.ser

ver,

.her

e’s

.wha

.you.sho

uld

.typ

mysql -h <hostname> -u <username> -p <password>

.you.inst

alled

.and.type

.ever

ything

.prop

erly,

.the.MySQ

.clie

.prog

ram

.will.intr

oduce

.itse

.and.

then.tak

.you.to.the.MyS

.com

mand

.lin

mysql>

.at.any.tim

.you.wan

.to.exi

.the.MyS

.cli

ent

.pro

gram,

.jus

.typ

.“qu

it”

.or.“ex

it.”

62.4.1 Creating a Database

To.create.a.database.and.use.it,.type.the.following.command.(don’t.forget.the.semicolon),.then.ENTER.

mysql> CREATE DATABASE databasename;

mysql> USE databasename;

Ex:

mysql> CREATE DATABASE employee;

mysql> USE employee;

.see.a.lis

.of.dat

abases

.ava

ilable,

.typ

.the.fol

lowing

.com

mand,

.the

.ENT

ER.

mysql> SHOW DATABASES;

62.4.2 Creating a table

To.create.a.table,.use.the.“CREATE.TABLE”.statement.

Syntax:

CREATE TABLE <table name> (

column_name1 data_type,

column_name2 data_type,

);

Exam

ple:

mysql> CREATE TABLE employeeinfo (

LastName varchar(15),

FirstName varchar(15),

Department varchar(15),

Employee_ID int

);

TABLE 62.1 SQL.Database.Table

Last.Name First.Name Employee.Department Employee.ID

Rives John Sales 2

Tent Tom Accounts 1

Hold Tim Technical 5

Development of Interactive Web Pages 62-9

To.view.tables,.type.the.following.command.

mysql> SHOW TABLES;

62.4.3 Modifying tables

To.delete.a.table,.type

mysql> DROP TABLE <tableName>;

.in

sert

.da

.in

.a.ta

ble,

.ty

mysql> INSERT INTO <table name>

(column1, column2, …)

VALUES (value1, value2, …);

Example:

mysql> INSERT INTO employeeinfo

(LastName, FirstName, Department, Employee_ID)

VALUES (Rives, John, Sales, 2);

.up

date

.da

.sto

red

.in.a.da

tabase

.ta

ble,

.ty

mysql> UPDATE <tableName> SET

<col_name>=<new_value>, …

WHERE <where clause>;

Example:

mysql> UPDATE employeeinfo SET FirstName='Johnny' WHERE

LastName='Rives' AND Employee_ID=2;

.de

lete

.a.re

cord

.fr

.th

.ta

ble

mysql> DELETE FROM table_name WHERE some_column=some_value;

Example:

mysql> DELETE FROM employeeinfo WHERE LastName='Tent';

.de

lete

.al

.ro

DELETE * FROM employeeinfo;

62.4.3.1

to Vie

w Data

.SE

LECT

.co

mmand

.is.us

.fo

.vi

ewing

.da

.sto

red

.in.yo

.da

tabase

.ta

bles.

Syntax:

SELECT column_name(s) FROM table_name;

Example

.1:.To.di

splay

.da

.fr

.co

lumns

.La

stName

.an

.De

partment.

mysql> SELECT LastName, Department from employeeinfo;

62-10 Industrial Communication Systems

Example.2:.To.display.all.data.that.is.in.the.employeeinfo.database.table,

mysql> SELECT * FROM employeeinfo;

62.4.3.2

WHErE Clau

.ext

ract

.tho

.rec

ords

.tha

.ful

ll

.spe

cic

.cri

teria

mysql> SELECT LastName, Department FROM employeeinfo WHERE

Employee_ID=2;

62.4.3.3

OrDEr BY Key

word

.sor

.rec

ords

.in.the.tab

mysql> SELECT * FROM employeeinfo ORDER BY Employee_ID DESC;

.sort.in.ascending.order,.use.ASC.instead.of.DESC.

62.5 Creating Dynamic Web Sites Using PHP and MySQL

We.are.going.to.discuss.some.simple.ways.to.create.a.dynamic.Web.site.. ese.include.connecting.to.

the.data

base

.thro

ugh

.PHP,.extr

acting

.data.that.sits.in.MySQ

.data

base,

.and.pres

enting

.it.as.a.part.of.

the.Web.pag

62.5.1 Connecting to Database

To.connect.to.a.database.using.PHP,.you.do.not.need.any.other.program..PHP.features.some.built-in.

func

tions

.tha

.can.con

nect,

.man

age

.and.dis

connect

.to.MyS

.dat

abase.

Syntax:

mysql_connect("localhost","username","password")

Since

.the.con

nection

.ret

urns

.an.ide

ntier,

.we.can.stor

.it.in.a.var

iable

.for.lat

.use

Example:

<?php

$contn=mysql_connect("localhost","username","password");

.dis

play

.the.err

.mes

sage

.whe

.con

nection

.fai

ls,

.“di

e”

.fun

ction

.ser

ves

.tha

.pur

pose.

.clo

.the.con

nection

Ex:

.mysql_close($con);

62.5.2 SQL Queries with PHP

To.send.SQL.queries.(commands).to.the.database.and.view.the.results.of.those.queries

Syntax:

mysql_query("query", connection_id);

Development of Interactive Web Pages 62-11

62.5.3 Creating a Database

To.create.a.database.on.MySQL,.use.the.CREATE.DATABASE.statement.

Example:

<?php

$contn=mysql_connect("localhost","username","password");

mysql_query("CREATE DATABASE employeeinfo",$contn);

62.5.4 Creating a table

To.create.a.Table,.use.the.CREATE.TABLE.statement.

Example:

<?php

//Establish connection to MySQL database.

$contn=mysql_connect("localhost","username","password");

//Create your database

mysql_query("CREATE DATABASE employee",$contn);

/*Select your database or for the matter, you can select any

database that you have already created.*/

mysql_select_db("employee", $contn);

// Create table

$tbl = "CREATE TABLE employeeinfo

(

LastName varchar(15),

FirstName varchar(15),

Department varchar(15),

Employee_ID int

)";

// Execute query

mysql_query($tbl,$contn);

//Close connection

mysql_close($contn);

.see.the.las

.err

.mes

sage

.gen

erated

.by.MyS

.ser

ver,

.mys

ql_error()returns

.a.tex

.des

cribing

.the.las

err

.me

ssage.

Example:

if (mysql_query($tbl)

) {

echo("Employee Table created</P>");

} else {

echo("Error creating employee table:". mysql_error()

);

}

62-12 Industrial Communication Systems

62.5.5 Insert, Update and Delete queries

To.insert.data.into.a.database.table,.use.INSERT.INTO.Statement.

Example:

mysql_query("INSERT INTO employeeinfo (LastName, FirstName,

Department, Employee_ID)

VALUES ('Rives', 'John', 'sales', '2')");

$_POST

.is.use

.to.col

lect

.dat

.fro

.a.for

.and.if.you.sub

stitute

.it.in.VAL

UES,

.par

ameters

.of.a.for

can.be.in

serted

.in

.a.ta

ble.

.up

date

.ex

isting

.re

cords

.in.a.ta

ble,

.us

.UP

DATE

.st

atement.

Example:

mysql_query("UPDATE employeeinfo SET LastName= 'Rives' WHERE

FirstName = 'John' AND Employee_ID = '2'

");

mysql_query("UPDATE employeeinfo SET LastName= 'Rives'

"WHERE FirstName = 'John' AND Employee_ID = '2'

");

.de

lete

.ex

isting

.re

cords,

.us

.DE

LETE

.st

atement,

mysql_query("DELETE FROM employeeinfo WHERE LastName='Tent'

");

62.

5.5.1

Sel

ect Query

.se

lect

.re

cords

.fr

.da

tabase,

.we.us

.th

.SE

LECT

.st

atement.

Example:

.select.all.the.records.from.the.table.employeeinfo

$result = mysql_query("SELECT * FROM employeeinfo");

.da

.re

turned

.by.my

sql_query

.is.sto

red

.in.th

.va

riable

.$r

esult.

Now

.we.use.mys

ql_fetch_array()

.fun

ction

.to.ret

urn

.to.the.rs

.row.of.the.tab

le.

.And.eac

.tim

.a.cal

to.my

sql_fetch_array()

.re

turns

.th

.ne

.ro

.in.th

.ta

ble.

Example:

while($row = mysql_fetch_array($result)

)

{

echo $row['LastName']. "

". $row['FirstName']. " ".

$row['Department']. "

". $row['Employee_ID'];

echo "<br />";

}

Output:

Rives John sales 2

Tent Tom accounts 1

Hold Tim technical 5