Part 1

Persistent DataWeb applications remember your setting by

means of a database linked to the site

Central Sales DatabaseA site such as Amazon has a central data store and

users may browse the content from different locations

To set this up we need two things…

A Database Management System Some sort of data aware objects

Database Management SystemsFor a commercial web site the following are

examples of suitable Database Management Systems (DBMS)

MySQLAn “open source” (i.e. free) DBMS that runs on

Windows, MAC and UNIX platforms

OracleA company that makes powerful DBMS

SQL ServerMicrosoft’s DBMS, a version of this comes “free” with

Visual Studio

Microsoft AccessOnly ten users may access the database at a

given time (This limitation may be overcome by means of using a different operating system e.g. Windows Server)not good for building your multimillion pound

online store

However…Most students are familiar with the applicationIt is part of the Microsoft OfficeIt is easy to set up and use

Data Aware ObjectsObjects are used allow our programs to control

computer technology

The email objectallows us to create emails

The SMTP client objectallows us to control an SMTP server, i.e. send emails.

The variable (object)allows us to store data in the RAM

Control objectsallow us to set up regions of the screen so the screen so

the user may interact with it.

ADO.NET (Active Data Objects)Used to control databases

Problem!

It is huge and complex and would need a year long course just to get to grips with it

The DatabaseTable ObjectA custom object written for this module

Allows simple control of a database

Hides ADO.NET so you can get on with the task at hand

DatabaseTable acts as a kind of “secretary”. You send it a simple command and then it uses ADO.NET on your behalf to interact with the database

Four Things we want to do Produce a list of records for searching or

so that the user may see them all at once

Add a new record to the database

Edit an existing record in the database

Delete a record

Structured Query LanguageSQL allows us to manipulate data in the databaseSQL combined with concatenation provides us

with a powerful tool to control the data

Consider the Following Data

The parameter MessageNo = 3

Add Validation