Widgets Inc

      Widgets is an MDI (Multiple Document Interface) database project series based on a fictional company which keeps inventory of and sells products.  The main goal of this project is to show the concepts of working with databases in code and get away from the bounds of the Visual Studio designer.  After going through this project you will have a better understanding of working with databases and how the designer generated code works behind the scenes.  Additional coding concepts will be focused on for handling code efficiently and cleanly to keep code organized, less cluttered and more generic to reduce code duplication.

    This project will also show how to work with the idea of parent/child relationships in your code rather than relations setup in the designer such as with a strongly typed dataset.  A SQLCE (SQL Server Compact Edition) 3.5 database will be used since this will be a local application where the database and the application will both reside on and be accessed only by the local workstation.  SQLCE does not support Stored procedures so this project will be using Dynamic T-SQL to issue commands to the database.  You can read more about Dynamic T-SQL and Stored Procedures in our articles and in the project series details. 

    How to handle relationships between tables and perform multiple commands one after another on multiple tables and database Normalization will also be covered in the series which is the designing of relational database tables to minimize duplication of data and keep consistency and integrity.  This helps make coding more efficient as well.  There will be focus on passing data more efficiently through the use of classes and function / subroutine parameters rather than variables which will help reduce code clutter and centralize generic code handling to perform different commands throughout the application from one subroutine or function.

    Search forms and data reporting using code will be implemented.  Input validation and error handling will be discussed and implemented such as when to use Try Catch blocks, when they are not necessary, why they are not needed and how to write code to prevent errors by "catching" them before they happen.  Using global objects both in the form classes and throughout the application and how to re-use them will also be covered.

    This project is not to show the best or the only way to write database applications.  It will show how you can take what you learn and apply it in new ways to meet your needs and preferences.  There is much debate over the best way to write code.  You need to make the code work for you.  This project will show you some of the methods that are used professionally and will help you prepare to work for a company developing software. 



Project Progression

    The Widgets Inc project will start with a very simple design focused on working in small sections.  The design and code will progressively be changed through a series of projects adding simple steps to increase the functionality of the application. 

    In the beginning of the project progression, code will be used in a design that might be considered bad design having all code inside of the form class or GUI (Graphical User Interface) layer.  Progressively code will be moved into classes, functions and subroutines to help you understand how you can create and use centralized code.

    Projects in the series will be added periodically as they are completed.  If you chose to receive email updates during your registration, emails will be sent out when each series project is released.  If you chose to not receive email updates and would like to change your account to add email notifications you can do so at the bottom of the page.



Requirements:

Visual Studio 2008
Visual Basic 2008 Express Edition
or Higher
 
* 2005 Users
     The files in each project can be added to a 2005 project using the Project Menu - Add Exisitng Item.  Be sure to remove Form1 which is created automatically with a new project and set MdiParent1 as the startup form in the Project Properties - Application tab.

DotNet Framework 2.0
SQL Server Compact Edition 3.5



Getting Started

    Details explaining each step in the series design and code can be viewed by selecting details under each project.  Each will explain the details for those changes and additional functionality specific to that particular part of the project.  Code will be commented in the projects as well.  Go through each project in order to understand the progression of the entire application.  The first project will explain in detail how to create the database in the Visual Studio designer and how the MDI applicaiton is setup.  The database will only consist of the tables and columns needed for each part of the series making the project very easy to follow and reproduce on your own. 

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			Widgets1

			Widgets2

			Widgets3

			Widgets4

			Widgets5

			Widgets6

			Widgets7

			Widgets8