PHP Overview

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PHP Overview

• PHP Hypertext Preprocessor
• Server-Side Scripting
• Code also included with HTML
• Pre-processed on server
• Browser gets only HTML and client-side code
• More secure than JavaScript
• More powerful than JavaScript
• File access, database access, etc.
• Less efficient than JavaScript for interactive
  features
• Must go back to the server

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PHP Overview

• Open source software
• Free, users can add features
• E.g., phpMyAdmin, DBMS connectivity
• Evolving documentation (www.php.net)
• Competitors
• Active Server Pages (Microsoft)
• Java servlets and JSP (Sun)
• Cold Fusion (Macromedia)

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PHP Overview

• Summary
• JavaScript is the sizzle, PHP is the substance
• Secure method for
• Processing form data
• More extensive calculations, manipulations
  possible
• Selective display of database data
• Updates, deletions from databases
• Separating content from design
• Keeping track of information from one web page to
  another
• E-mailing information
• Validating users (logins, privileges, etc.)
• Etc.

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PHP Overview

• Basic examples
• Output
• Use of built-in functions (and php.net)
• User-written functions
• Control structures
• Processing form input
• Processing querystring input
• POST and GET methods
• Session variables

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PHP Overview
Try it

• Two DB examples (quick look first)
• List all customer information from database
• Design
• Connect to the DB server
• Select the DB we want to use (CS19)
• Get the Customer information from the DB
• Display it using HTML
• Disconnect from the DB
• Note Compare to the steps we use to directly
  connect to the DB using phpMyAdmin

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PHP Overview
Connect to the DB server and select the DB
CS19 lt?php include ("/home/ktreu/aux/common_db
.inc") linkID mysql_connect("localhost",dbu
sername,dbuserpassword) or die ("Could not
connect " . mysql_error()) mysql_select_db("C
S19", linkID) or die ("Unable to select db "
. mysql_error())
Notes php delimiter, variables, including
external files, error checking
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PHP Overview
Get the list of Customers from the DB SQL
"SELECT FROM Customers ORDER BY
name" allValues mysql_query(SQL,
linkID) if (!allValues) echo "Could
not successfully run query (SQL) from DB " .
mysql_error() exit
Notes use of SQL, possibility of multiple links
to DB server, built-in MySQL functions, error
checking, contents of allValues
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PHP Overview
echo "lth4gtAll Customers Ordered by Last
Namelt/h4gt" echo "ltTABLE BORDER1
CELLPADDING8gt" echo "ltTRgtltTDgtltBgtCustomer
Numberlt/Bgtlt/TDgtltTDgtltBgtNamelt/Bgtlt/TDgtltTDgtltBgtPhonelt/B
gtlt/TDgt" while (thisValue mysql_fetch_array(al
lValues)) echo "ltTRgt" echo "ltTDgt" .
thisValue"custnum" . "lt/TDgt" echo "ltTDgt" .
thisValue"name" . "lt/TDgt" echo "ltTDgt" .
thisValue"phone" . "lt/TDgt" echo
"lt/TRgt" echo "lt/TABLEgt" mysql_close(linkID)
?gt
Notes printing HTML, looping, accessing each
record from the query one by one, closing the
connection
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PHP Overview

• What changes would be needed to get different
  data?
• List all Product information?
• List all products sold in March with the name of
  the customer who purchased them?
• Etc.

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PHP Overview
Try it

• Another example (quick look)
• List all customer information from database for a
  specific customer
• Design
• Get the desired customer number from the user
• Connect to the DB server
• Select the DB we want to use (CS19)
• Get the information for the customer with the
  desired customer number from the DB
• Display it using HTML
• Disconnect from the DB

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PHP Overview
Write a form to get the customer number ltform
method"post" action"listCustomersByCustnum.php"gt
Please enter a Customer Number ltinput
type"text" name"custnum" length"4"
maxlength"4"gt ltbrgt ltinput type"submit"
value"Click for Customer Info"gt lt/formgt
Notes method and action attributes of the form
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PHP Overview
Only two changes necessary in the PHP
code custno _POST'custnum' SQL
"SELECT FROM Customers WHERE custnumcustno"
allValues mysql_query(SQL, linkID) if
(!allValues) echo "Could not
successfully run query (SQL) from DB " .
mysql_error() exit
Notes Accessing the form data, using it in a
query, significance of double quotes
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Additions

• Edit
• Delete
• Insert
• Admin functions
• Other tips and tricks