Part 1

Persistent Data Web applications remember your setting by means of a database linked to the site

Central Sales Database A 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 Systems For a commercial web site the following are examples of suitable Database Management Systems (DBMS) MySQL An “open source” (i.e. free) DBMS that runs on Windows, MAC and UNIX platforms Oracle A company that makes powerful DBMS SQL Server Microsoft’s DBMS, a version of this comes “free” with Visual Studio

Microsoft Access Only 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 application It is part of the Microsoft Office It is easy to set up and use

Data Aware Objects Objects are used allow our programs to control computer technology The object allows us to create s The SMTP client object allows us to control an SMTP server, i.e. send s. The variable (object) allows us to store data in the RAM Control objects allow 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 Object A 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 Language SQL allows us to manipulate data in the database SQL combined with concatenation provides us with a powerful tool to control the data

Consider the Following Data The parameter MessageNo = 3

Add Validation