Server-side programming - ASP

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Session 6

• Server-side programming - ASP

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What is ASP?

• An ASP page is an HTML page interspersed with
  server-side
• code.
• The .ASP extension instead of .HTM denotes
  server-side code
• to the hosting Web server.
• You can use any text editor to create or change
  an ASP file

Sets the default for the page
lt_at_LANGUAGE "JavaScript"gt lt var varSurname
Request.form("surname") gt lthtmlgt ltbodygt lt sql
"Select from tblStock" gt THIS IS
HTML Surname ltvarSurnamegt
Gets data from form on previous page
The ASP is between lt and gt
Outputs the variables content
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Open Database Connectivity(ODBC)
These databases know how to interact with ODBC

• ODBC is an intermediary technology that allows
  databases made by different manufacturers to
  communicate with different interfaces e.g. ASP
  pages.
• The web server has ODBC drivers installed upon it
  which interpret the dialogue into a common
  language that each database understands.

Adapted from Resselman, 2000
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Browsers

• Display data primarily in HTML format.
• Accept user input from HTML form elements
• ASP pages are a mixture of hard-coded HTML (menu
  bars, other static page content) and dynamically
  generated HTML.
• ASP (operating at the server-side) must therefore
  send the data from the server to the client in
  HTML format. All the calculations for doing this
  are performed at the server side, using the
  server's processor.

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Client
HTTP Request
Web Server
HTTP Response
Components
VBScript
IIS
ActiveX Data Objects (ADO)
JavaScript
ActiveX Scripting Engines
Database
ASP File
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Stages for ASP

1. Client requests ASP page from server
2. HTML and script code are separated.
3. Script code is parsed, syntax checked and
   compiled by Web server by appropriate scripting
   engine
4. Code is executed by the appropriate scripting
   engine
5. Script output and static HTML code are merged
6. Final HTML is sent back to the user

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Anatomy of an .asp Page
lthtmlgt ltheadgt lt/headgt ltbodygt lt/bodygt lt/htmlgt
Note the code appears where the data will be
output on screen.
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Returning Records from a DB Using ASP

• Open a connection to the database, using the
  connection object.
• Create a query string variable containing the SQL
  for the query.
• Create a recordset object, then run the query on
  it.
• Loop through the records and format and display
  each as HTML.

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lt_at_ LANGUAGE"JAVASCRIPT" gt lt myconn
CreateObject("ADODB.Connection") rs
CreateObject("ADODB.Recordset") myDB
"DriverMicrosoft Access Driver
(.mdb)DBQe\\webareas\\sr65\\sdg.mdb"
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sql "Select from tblStock order by
Stock_id" rsmyconn.Execute(sql) while (!
rs.eof) gt Item ltrs("Description")gtltbr
/gt lt rs.MoveNext rs.Close gt