Scott Mitchell

June 2006

Download the ASPNET_Data_Tutorial_1_CS.exe sample code.

Contents of Tutorial 1 (Visual C#)

Introduction
Step 1: Creating a Web Project and Connecting to the Database
Step 2: Creating the Data Access Layer
Step 3: Adding Parameterized Methods to the Data Access Layer
Step 4: Inserting, Updating, and Deleting Data
Step 5: Completing the Data Access Layer
Summary

Introduction

As Web developers, our lives revolve around working with data. We create databases to store the data, code to retrieve and modify it, and web pages to collect and summarize it. This is the first tutorial in a lengthy series that will explore techniques for implementing these common patterns in ASP.NET 2.0. We'll start with creating a software architecture composed of a Data Access Layer (DAL) using Typed DataSets, a Business Logic Layer (BLL) that enforces custom business rules, and a presentation layer composed of ASP.NET pages that share a common page layout. Once this backend groundwork has been laid, we'll move into reporting, showing how to display, summarize, collect, and validate data from a web application. These tutorials are geared to be concise and provide step-by-step instructions with plenty of screen shots to walk you through the process visually. Each tutorial is available in C# and Visual Basic versions and includes a download of the complete code used. (This first tutorial is quite lengthy, but the rest are presented in much more digestible chunks.)

For these tutorials we'll be using a Microsoft SQL Server 2005 Express Edition version of the Northwind database placed in the App_Data directory. In addition to the database file, the App_Data folder also contains the SQL scripts for creating the database, in case you want to use a different database version. These scripts can be also be downloaded directly from Microsoft, if you'd prefer. If you use a different SQL Server version of the Northwind database, you will need to update the NORTHWNDConnectionString setting in the application's Web.config file. The web application was built using Visual Studio 2005 Professional Edition as a file system-based Web site project. However, all of the tutorials will work equally well with the free version of Visual Studio 2005, Visual Web Developerhttp://msdn.microsoft.com/vstudio/express/vwd/.

In this tutorial we'll start from the very beginning and create the Data Access Layer (DAL), followed by creating the Business Logic Layer (BLL) in the second tutorial, and working on page layout and navigation in the third. The tutorials after the third one will build upon the foundation laid in the first three. We've got a lot to cover in this first tutorial, so fire up Visual Studio and let's get started!

Step 1: Creating a Web Project and Connecting to the Database

Before we can create our Data Access Layer (DAL), we first need to create a web site and setup our database. Start by creating a new file system-based ASP.NET web site. To accomplish this, go to the File menu and choose New Web Site, displaying the New Web Site dialog box. Choose the ASP.NET Web Site template, set the Location drop-down list to File System, choose a folder to place the web site, and set the language to C#.

Figure 1. Create a New File System-Based Web Site

This will create a new web site with a Default.aspx ASP.NET page and an App_Data folder.

With the web site created, the next step is to add a reference to the database in Visual Studio's Server Explorer. By adding a database to the Server Explorer you can add tables, stored procedures, views, and so on all from within Visual Studio. You can also view table data or create your own queries either by hand or graphically via the Query Builder. Furthermore, when we build the Typed DataSets for the DAL we'll need to point Visual Studio to the database from which the Typed DataSets should be constructed. While we can provide this connection information at that point in time, Visual Studio automatically populates a drop-down list of the databases already registered in the Server Explorer.

The steps for adding the Northwind database to the Server Explorer depend on whether you want to use the SQL Server 2005 Express Edition database in the App_Data folder or if you have a Microsoft SQL Server 2000 or 2005 database server setup that you want to use instead.

Using a Database in the App_Data Folder

If you do not have a SQL Server 2000 or 2005 database server to connect to, or you simply want to avoid having to add the database to a database server, you can use the SQL Server 2005 Express Edition version of the Northwind database that is located in the downloaded website's App_Data folder (NORTHWND.MDF).

A database placed in the App_Data folder is automatically added to the Server Explorer. Assuming you have SQL Server 2005 Express Edition installed on your machine you should see a node named NORTHWND.MDF in the Server Explorer, which you can expand and explore its tables, views, stored procedure, and so on (see Figure 2).

The App_Data folder can also hold Microsoft Access .mdb files, which, like their SQL Server counterparts, are automatically added to the Server Explorer. If you don't want to use any of the SQL Server options, you can always download a Microsoft Access version of the Northwind database file and drop into the App_Data directory. Keep in mind, however, that Access databases aren't as feature-rich as SQL Server, and aren't designed to be used in web site scenarios. Furthermore, a couple of the 35+ tutorials will utilize certain database-level features that aren't supported by Access.

Connecting to the Database in a Microsoft SQL Server 2000 or 2005 Database Server

Alternatively, you may connect to a Northwind database installed on a database server. If the database server does not already have the Northwind database installed, you first must add it to database server by running the installation script included in this tutorial's download or by downloading the SQL Server 2000 version of Northwind and installation script directly from Microsoft's Web site.

Once you have the database installed, go to the Server Explorer in Visual Studio, right-click on the Data Connections node, and choose Add Connection. If you don't see the Server Explorer go to the View / Server Explorer, or hit Ctrl+Alt+S. This will bring up the Add Connection dialog box, where you can specify the server to connect to, the authentication information, and the database name. Once you have successfully configured the database connection information and clicked the OK button, the database will be added as a node underneath the Data Connections node. You can expand the database node to explore its tables, views, stored procedures, and so on.

Figure 2. Add a Connection to Your Database Server's Northwind Database

 

 

 

 

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