Dr. Dobb's is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.


Channels ▼
RSS

Database

Using LINQ-to-SQL XML Mapping Files


Dan Wahlin (Microsoft Most Valuable Professional for ASP.NET and XML Web Services) is a .NET development instructor and architecture consultant at Interface Technical Training. Dan founded the XML for ASP.NET Developers site, which focuses on using ASP.NET, XML, Silverlight, AJAX, and Web Services on .NET and runs smartwebcontrols.com. He's also on the INETA Speaker's Bureau and speaks at several conferences. Dan has co-authored/authored several different books on .NET, including ASP.NET 2.0 MVP Hacks, Professional ASP.NET AJAX, XML for ASP.NET Developers and is currently working on a new book on Silverlight 2. Dan blogs at http://weblogs.asp.net/dwahlin.

.NET 3.5's LINQ-to-SQL functionality provides a great way to write data access layer code that automatically handles mapping relational data to object properties. Although I generally prefer to use stored procedures when performing insert, update, or delete operations against a database, I still use LINQ-to-SQL in projects since it eliminates the time I used to spend creating SqlParameter objects or writing AddWithValue() parameter statements. Overall, LINQ-to-SQL has made me much more productive as a developer.

Most of the samples involving LINQ-to-SQL involve using the designer built-into Visual Studio 2008 since it's very productive. The LINQ-to-SQL designer is a great way to go and normally what I use when doing my Object-Relational Mapping (ORM). I recently had someone ask if using the LINQ-to-SQL designer was required to leverage LINQ-to-SQL in their applications. They had existing data entity classes that they wanted to use and didn't want to re-create them using the designer. In situations like this you can use built-in XML mapping features available in LINQ-to-SQL to get around using the designer if desired. Going this route leads to writing more custom code and XML mapping files but also provides the ultimate in control especially if your data entity classes are created by another tool, you don't want your classes littered with LINQ-to-SQL attributes, or you have some other reason for not wanting to use the designer. In this article, I provide a step-by-step introduction to working with LINQ-to-SQL XML mapping files. The sample code that accompanies this article is available here.

Step 1. Create the Data Entity Class

If you're not using the LINQ-to-SQL designer, then you'll need to create your own data entity classes (or use third-party tools to create them) that can hold data from the target database. If you already have existing data entity classes that you want to use then you can skip this step. Here's a simple Customer class capable of holding some of the data found in the Customer table in the AdventureWorksLT database.


namespace Model
{
    public class Customer
    {
        public int CustomerID { get; set; }
        public string Title { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public DateTime ModifiedDate { get; set; }
    }
}

A diagram of the Customer table follows:

Customer Table


Related Reading


More Insights






Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

 
Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.