ECommerce Infrastructure

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E-CommerceInfrastructure Security

• Lecture 11
• VB and DB(DDWS 51-84 165-214)

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Agenda

• Install VB 6.0
• DB Basics - Review
• Creating a DB-enabled Visual Basic
  ActiveX-driven web site

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Our Goal - An ActiveX DB Control

• Recall our previous discussion of ActiveX
• Wed like to add DB capability to our Web site

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Installing VB 6.0

• Grab a CD-Rom shove it in
• Follow the on-screen commands
• Key 325-1328043
• Select VB Professional
• TYPICAL install is fine
• Reboot w/ disc in drive
• No need for server tools
• Uncheck MSDN registration

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Database Review

• Im assuming Chapter 3 was review for you
• Youve taken ITSK1701(DB Applications - Access)
• Very Briefly

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Structured Query Language (SQL)

• Standard query language of relational databases
• Desirable to use as query language to communicate
  between the Web pages and the database
• Easier to migrate Web page applications to other
  database platforms
• Structure and syntax of SQL is the same across
  most database management systems (DBMSs)

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MS Access Components

• Access application environment
• User interface used to create tables, manage
  data, and create and manage database objects
• Jet database engine
• Underlying DBMS that manages database tables and
  processes SQL commands

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ODBC

• Open Database Connectivity
• Standard database communication protocol
• Enables a database application to interact with
  different DBMSs

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An Overview
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Database Queries

• Question that can be answered by data stored in a
  database
• Retrieve data from single or related data from
  multiple database tables
• Perform mathematical functions on retrieved data
• Group retrieved records and perform group
  functions

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Various Means of Defining Queries

• Query by example (QBE)
• Technique used in Access to create queries
• Jet SQL
• Commands unique for the SQL syntax used by the
  Jet database engine

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Views in Access

• Design View used to create QBE queries
• SQL View used to view the SQL text associated
  with QBE queries and to enter SQL queries
  directly
• Datasheet View used to view query results

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Making Use of SQL

• Were going to use VB
• Well create an application
• Then well interface w/ a DB
• And convert the application into an ActiveX
  control

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OK - Now to Visual Basic

• Object-oriented programming language
• Event driven
• Project file - the master document
• Form - interface responsive code
• Module - defines commonly-used code in the way of
  procedures functions

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Visual Basic Projects

• When VB is started, a new project is created,
  which corresponds to an individual user
  application
• When you create a new project, you can select the
  type of project it will be, which specifies how
  the project file is compiled

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Visual Basic Projects
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The VB IDE
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Saving Visual Basic Projects

• A VB project is saved in a file with a .vbp
  extension
• Forms are saved in files with an .frm extension
• When you create a new project, it is very
  important to always save the project (.vbp) file
  and the form (.frm) file in the same folder in
  your file system

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Using Visual Basic with a Database

• ODBC driver
• Low-level program that translates messages from
  an application into the syntax expected by a
  specific database
• Each different type a database requires a
  different ODBC driver
• Always runs on the client workstation

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Using Visual Basic with a Database

• Need to communicate with ODBC drivers
• Microsoft has developed a variety
• Data Access Objects (DAO)
• Remote Data Objects (RDO)
• ActiveX Data Objects (ADO)

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Using Visual Basic with a Database

• DAO
• Available in most applications that support
  database connectivity, but cannot support action
  queries that change content in some databases
• RDO
• Full-featured, but only available in Microsofts
  high-end enterprise-level programming
  environments
• ADO
• Full-featured, is available in most Microsoft
  environments, and supports most types of queries

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Using Visual Basic with a Database
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Using Visual Basic with a Database
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Creating an ActiveX Data Control

• ActiveX data control
• A control that is displayed on a form
• Different from an ordinary form control because
  it is associated with a recordset
• A specific set of database records based on a SQL
  query

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Creating an ActiveX Data Control
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Creating an ActiveX Data Control

• To create an ADO data control, you must add a
  type library to your project
• A type library is a library of code that has
  programs, such as additional controls, that you
  can add to VB IDE and then use in your project

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Using Code to Process Data

• With a programmatic data connection
• All of the commands to create the connections and
  execute SQL commands are specified in a VB
  standard module
• User does not have to interact with a visible
  data control to perform database operations

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Using Code to Process Data
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A Simple DB Application
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Putting A Project Together

• Start up a Standard EXE
• Drop down 3 text boxes
• Add the ADO Control
• Right click Control View
• Select MS ADO Data Control 6.0
• Have it point to the clearwater DB
• Set the RecordSource SQL toSELECT FROM item
• Set the DataSource and DataField properties for
  each of the three text boxes

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Making the ActiveX Document

• Wed like to be able to pull this application
  into the browser
• Well make a new ActiveX Document project
• Itll make use of the project we just made

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Creating the ActiveX Document

• Create new ActiveX Document project
• Project Add Form Existing browse to the
  form1
• Well need to make this form open by default, so
  edit the Initialize method of the ActiveX
  Document form1.show 1

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Creating the Executable

• We need to create the executable and the display
  file for our ActiveX Document
• File Make PROJECTNAME.exe
• Select location
• Exit VB
• Open IE and browse to the VBD file
• (note, you might have to tell your OS what
  program to use to run the VBD file - use
  iexplorer

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Packaging

• Wed like to take it all a bit further
• The VB Install Package Wizard will determine
  dependencies, etc. so that the application can be
  distributed
• We wont get into the gory details here, but be
  aware that there are dependencies and registry
  entries that you need to be aware of.

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Thinking Ahead

• Well go into more detail on developing
  DB-enabled Web sites, especially for project 8
• For now, you should be able to follow tonights
  lecture and the content of Chapter 6 - coding in
  VB and publishing data (via ActiveX Documents) to
  the web
• Next week - Load balancing (get a handout),
  Review Midterm 1 (Infrastructure)

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Have a Great Weekend
FIN