BA394 VBScript Lecture 7

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BA394 VBScript Lecture 7

• Tim Faltemier

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In this Lecture

• Finish up the SQL information that you should
  know (ADO)
• Begin to talk about XML
• Show A few examples and the various uses

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ActiveX Data Objects (ADO)

• ADO is the primary way in which you will use to
  interact with the database (SQL Statements are
  EXECUTED with ADO).
• ADO extensions are automatically installed when
  someone installs IIS (Microsofts Web Server)
• Note USUALLY only available on Windows machines
  NOT very versatile

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Accessing a Database

• In order to access a SQL database you need to do
  the following things in ADO.
• Create an ADO connection to a database
• Set objConn Server.CreateObject(ADODB.Connectio
  n)
• Open the database connection
• objConn.ConnectionString strConnect
  
• objConn.Open
• Create an ADO Recordset
• Set rsName Server.CreateObject("ADODB.Recordset"
  )

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Accessing a Database (II)

• Open the Recordset
• rsName.Open strSQL, objConn
• Extract the data you need from the Recordset.
• EmailAddress rsName(Email")
• Close the Recordset
• rsName.close
• Set rsName nothing
• Close the connection
• objConn.close
• Set objConn nothing

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ADO Access

• Now that you know the basic sequence of commands
  you can alter any part to give you different
  results.
• The important things to remember are
• You should ALWAYS close a connection after your
  finished using it. This prevents memory leaks in
  your application.
• When accessing the data in a recordset, always
  check to see if the recordset contains any
  values, if it does not display the appropriate
  message (Otherwise error will occur).

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ADO Access (II)

• Although it is very easy to actually retreive
  data from a database, it is very difficult to use
  it effectively.
• Try and use as much HTML around your data as
  possible. The more you use, the more dynamic
  your site is.
• For example ltA hrefltrsName(WebAddress)gtgt
  ltrsName(CustomerName)gtlt/agt
• The above will print out a dynamic web address
  and customer name in the form of a link (which
  could be useful later on)

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Extensible Markup Language (XML)

• A common joke that is told in XML circles (and at
  many interviews) is
• Question When should I use XML
• Answer When you need a buzzword in your resume.
• XML is a markup language just like HTML
• It is mainly used to describe data for use with
  transfers etc.

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XML (II)

• In HTML you have predefined tags (ltpgt, ltBRgt,
  ltHRgt, etc) in XML however you do not.
• XML uses what you will commonly hear as a
  Document Type Definition (DTD) to describe the
  data that it passes.
• In the next few slides, we will look deeper into
  those facts.

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XML vs. HTML

• XML is not a replacement for HTML as you may
  believe, as they both do totally different
  things.
• XML was designed to describe data and to focus
  on what data is
• HTML on the other hand was designed to display
  data and to focus directly on how the data looks

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XML What it does

• In short, XML does not DO anything
• It was created as a way to structure, store, and
  send information.
• Look at the following example message stored in
  XML on the next slide
• You will notice that it has a clear cut
  structure, but if you were to put it in a HTML
  document nothing would happen (or at least not
  what you intended)

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XML Message Example

• ltMessagegt
• lttogtJohnlt/togt
• ltfromgtTimlt/fromgt
• ltheadinggtLook what I can dolt/headinggt
• ltbodygtWho would have thought I could do this with
  XML?lt/bodygt
• lt/Messagegt
• Notice in the message, I was free to create
  whatever tags I wanted in order to describe the
  data I was to use.

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Final note on XML

• Next week, I will start to show you some basic
  uses for XML and how we can begin to incorporate
  it into the projects (maybe)
• In short XML can be a very useful and powerful
  tool in your arsenal.
• If there is anything to be taken from this
  lecture, it is that XML is not useful in itself
  but with the use of other applications (and good
  standards) it can be very powerful.

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Questions or Comments
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Final Notes

• For the next quiz, make sure you look at and
  understand all of the examples from my site and
  read the lecture notes.
• Also make SURE you check back on the website
  before the quiz next week as there may be changes
  noted etc..
• Finally if you have any other questions or
  problems dont hesitate to email me.