PHP Case Studies

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PHP Case Studies
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Sending Mail

• mail (to, subject, message, headers )
• Can be used to send mail from a correctly
  configured php system
• To confirm registration and email addresses
• Send users information

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Auto Increment Fields

• Specify a field that is automatically incremented
• orderNum int autoincrement primary key
• Creates a unique key
• Ensures simultaneous updates do not create
  duplicate values

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Identifying Autoincrement Updated Value

• After inserting values into table that has an
  auto-increment field
• mysql_query("INSERT INTO trades
  (sellid,isbn,price,buysell) VALUES ('01001000',
  '1234567', '99.99', 'sell') ")
• Use mysql_insert_id() to find what was the value
  automatically inserted
• printf("Last inserted record has id d\n",
  mysql_insert_id())

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Trading Example

• Illustrating use of Php and Databases
• Database definition
• create table trades (
• tradeid int auto_increment primary key,
• buyid char(8),
• sellid char(8),
• isbn varchar(40),
• price float,
• buysell varchar(4)
• )

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Trading Example 2

• Trading Submission Form
• ltform method'post' action'index.php'gt
• Student IDltinput type'text' name'studid'/gtltbrgt
• Book ISBNltinput type'text' name'isbn'/gtltbrgt
• Priceltinput type'text' name'price'/gtltbrgt
• Buyltinput type'radio' name'buysell'
  value'buy' checked/gt
• Sellltinput type'radio' name'buysell'
  value'sell'/gtltbrgt
• ltinput type'submit' value'submit'/gt
• lt/formgt

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Trading Example 3

• Connect to Database
• db mysql_connect("localhost", "root")
• mysql_select_db("ass1",db)
• Create query and fetch first row
• result mysql_query("SELECT tradeid,buyid,sellid
  ,isbn,price,buysell FROM trades",db)
• myrow mysql_fetch_row(result)

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Trading Example 4

• Display Current Trades
• if(myrowfalse)
• echo "lth2gtNo trades in databaselt/h2gt"
• else
• echo "lttable border1gt\n"
• echo "lttrgtlttdgtTrade IDlt/tdgtlttdgtBuy Student
  IDlt/tdgtlttdgtSell Student IDlt/tdgtlttdgtISBNlt/tdgtlttdgtPr
  icelt/tdgtlttdgtBuySelllt/tdgtlt/trgt\n"
• do
• printf("lttrgtlttdgtslt/tdgtlttdgtslt/tdgtlttdgtslt/tdgtlttdgt
  slt/tdgtlttdgtslt/tdgtlttdgtslt/tdgtlt/trgt\n",
• myrow0,myrow1, myrow2, myrow3,
  myrow4, myrow5)
• while (myrow mysql_fetch_row(result))
• echo "lt/tablegt\n"

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Trading Example 5

• Extract posted values
• studid_POST'studid'
• isbn_POST'isbn'
• price_POST'price'
• buysell_POST'buysell'

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Trading Example 6

• SQL statements
• Select possible matching buy bids for my sell bid
• SELECT tradeid,buyid,sellid,isbn,price,buysell
  FROM trades where isbn'isbn' and buysell 'buy'
  and price gt price order by price DESC"

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Trading Example 7

• SQL statements
• Insert current sell bid into database
• "INSERT INTO trades (sellid,isbn,price,buysell)
  VALUES ('studid','isbn','price','buysell')

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Trading Example 8

• SQL statements
• Modify the best matching buy bid with my sell bid
• UPDATE trades set sellid'studid',
  buysell'sold' where tradeid'myrow0'

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Shopping Cart

• Product Selection Form
• ltform method"post" action"Shopping.php"gt
• ltinput type"hidden" name"addproducts"
  value"add"/gt
• ltinput type"hidden" name"IDs"
  value"1000,2000,3000"/gt
• ..PRODUCTS.
• ltinput type"submit" value"add"/gt
• lt/formgt

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Shopping Cart 2

• Product Displayed
• ProductRadio
• ltinput type"hidden" name"prodID1000name"
  value"Radio"/gt
• Price49.99ltinput type"hidden"
  name"prodID1000price" value"49.99"/gt
• Numberltinput type"text" name"prodID1000num"
  value"0"/gt

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Shopping Cart 3

• Cart Item class definition
• class cartitem
• var prodID
• var name
• var price
• var number
• function cartitem(pID, n, p, num)
• this-gtprodIDpID
• this-gtnamen
• this-gtpricep
• this-gtnumbernum

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Shopping Cart 4

• Processing Product List 1000,2000,3000
• count0
• IDlist array(10)
• whole_POST'IDs'
• do
• morestrstr(whole,',')
• IDlistcountsubstr(whole,0,strlen(whole)-
  strlen(more))
• wholesubstr(more,1,strlen(more))
• count
• while (more!false)

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Shopping Cart 5

• Retrieving Submitted Values
• for(c0cltcountc)
• prodIDIDlistc
• name_POST'prodID'.prodID.'name'
• price_POST'prodID'.prodID.'price'
• number_POST'prodID'.prodID.'num'
• if(number1gt0)
• newCartItem new cartitem(prodID, name,
  price, number)
• _SESSION'prodID'.prodIDnewCartItem

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Shopping Cart 5

• Display Shopping Cart
• echo "lth3gtShopping Cart Contentlt/h3gt"
• foreach ( _SESSION as key gt val)
• if(substr(key,0,6)'prodID')
• echo "nameval-gtname
• prodIDval-gtprodID
• priceval-gtprice
• numberval-gtnumberltbrgt"

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Summary
Main points to remember Mail function Auto
increment Fields Trade Example Shopping Cart