All of the tutorials we’ve examined so far have used a tiered architecture consisting of presentation, Business Logic, and Data Access layers. The Data Access Layer (DAL) was crafted in the first tutorial (Creating a Data Access Layer) and the Business Logic Layer in the second (Creating a Business Logic Layer). Starting with the Displaying Data With the ObjectDataSource tutorial, we saw how to use ASP.NET 2.0’s new ObjectDataSource control to declaratively interface with the architecture from the presentation layer.

While all of the tutorials so far have used the architecture to work with data, it is also possible to access, insert, update, and delete database data directly from an ASP.NET page, bypassing the architecture. Doing so places the specific database queries and business logic directly in the web page. For sufficiently large or complex applications, designing, implementing, and using a tiered architecture is vitally important for the success, updatability, and maintainability of the application. Developing a robust architecture, however, can be overkill when creating exceedingly simple, one­off applications.

ASP.NET 2.0 provides five built­in data source controls – SqlDataSource, AccessDataSource, ObjectDataSource, XmlDataSource, and SiteMapDataSource. The SqlDataSource can be used to access and modify data directly from a relational database, including Microsoft SQL Server, Microsoft Access, Oracle, MySQL, and others. In this tutorial and the next three, we’ll examine how to work with the SqlDataSource control, exploring how to query and filter database data, as well as how to use the SqlDataSource to insert, update, and delete data.

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