The WROBA (WRox Online Banking Application) case study used in this book uses a theme you may be familiar with – online banking. In fact, what we are going to develop during the first part of the book is a desktop based application – it still counts as online, in that it will enable a user sitting at their desk to carry out various banking activities, even though it will have a Visual Basic form type user interface.
The functionality of the case study was
arrived at by careful analysis of the business requirements of a hypothetical
client (Big Bank) and this is covered in Chapter 6. But so we're all clear about
where we are heading, let's highlight some of the major parts of WROBA. There
are two sides to the application;
a customer side and an administration side.
The customer side will:
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Show the status of the users accounts (two accounts are permissible Checking and Saving,
but only one of each per card) -
Allow previous transactions to be viewed
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Allow user passwords to be changed
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Allow users to add or edit payee details
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Allow users to move money between accounts
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Allow users to pay bills to payees
The administration side of the application offers a separate login for designated administrators, and allows the administrator to:
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Add and delete new accounts (as represented by cards)
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Lock and unlock cards that have fallen foul either of the login system (too many wrong login attempts) or the banking authorities
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Add and edit bank details (this feature is not fully implemented in our fledgling application)
Let's have a look at how this initial version relates to the 3-tier architecture we've previously looked at:
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The data tier consists of two units – a SQL Server 7.0 database (called BigBank) that contains both data and stored procedures for accessing and operating on that data, and the Bank_DB.dll component. We'll be designing and creating the database in Chapter 9, developing stored procedures in Chapter 10, and coding the COM component in Chapter 12.
The business tier consists of one COM component – Bank_Bus.dll that we'll code in Chapter 13.
The user tier functionality is provided by Bank_UI.exe – although it could be split into two projects, we have dealt with it as one. We'll consider the customer side of the interface in Chapter 14 and the administration side in Chapter 15.
In terms of the Windows DNA model, we're using SQL Server 7.0 to manage the data, UDA as we code the Bank_DB.dll COM component, and MTS (or COM+ depending on the platform) to provide an environment for Bank_Bus,dll and Bank_DB.dll to operate in. We haven't talked about ASP and IIS here, but when we show how to extend the WROBA case study and Web-enable it in Chapter 17, those products will also make an appearance.
Since it's a mere case study, there is some simplification. There are areas, which we highlight, that the enthusiastic reader may like to improve upon. We've made no attempts to implement deposit and withdrawal functionality, since there is no cash drawer, and no electronic checks or credit card accounts are implemented.
Just as a taste of what we'll be building, the following illustration shows the Information menu of the customer interface part of the application:
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As we said previously, if you want to work through the book and develop the application as you read along, that would be great. But you may also find it helpful to see the final working version, so you know what we're aiming at – if that's the case the code can be downloaded from www.wrox.com.
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