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    <p>Linq To SQL is great for single tier design. Not so great for a <strong>disconnected model</strong> or <strong>multi tier environment</strong>.</p> <p>The above code only inserts a single User into the database. If you fire up MSSQL SQL Server Profiler or connect up the log to the output in visual studio. You should see</p> <pre><code>//Hookup the log to the output in visual studio using (var db = new UserDataContext()) { db.Log = Console.Out; } INSERT INTO User VALUES (value1, value2, value3,...) </code></pre> <p>To update the the user your code should look at somthing like</p> <pre><code>public void UpdateUser(String username, String password, int userId) { using (var db = new UserDataContext()) { //Get Row From Database Marching Id var user = db.user.Single(p =&gt; p.Id = userId); //Update Values user.Username = username; user.Password = password; //Save To The Database db.SubmitChanges(); } } //Get All Users From Database public IEnumerable&lt;User&gt; GetAllUsers() { using (var db = new UserDataContext()) { //Get Row From Database Matching Id var users = from user in db.user select user; return users.ToList(); } } //To display the data just enumerate through the enumeration that is returned. var users = BusinessInstance.GetAllUsers(); foreach (var user in users) { //user is the current item } </code></pre> <p>You should make your that you are using your database contract every time you do a unit of work. (because the database context using transaction by default, and this can get ugly, <strong>don't bother about performance with constructing the database context!</strong>)</p> <p>Usually when you work with a multi tier environment, you would create a seperate <a href="http://en.wikipedia.org/wiki/POCO" rel="nofollow noreferrer">POCO</a>'s when passing them over the wire(network). </p> <p><a href="http://code.google.com/p/ncommon/" rel="nofollow noreferrer">NCommon</a> is a great abstraction for Linq to Sql, should handle business validation and rules.</p> <p>Note. Its good practice to <a href="http://en.wikipedia.org/wiki/MD5" rel="nofollow noreferrer">hash password values</a> in a database.</p> <p>Check out <a href="http://weblogs.asp.net/scottgu/" rel="nofollow noreferrer">ScottGu's blog for a quick q&amp;a and basics on linq</a></p>
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    1. COi want to get list of all users with a method in my UserBLL class how can i do that?
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    2. COupdated content
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    3. COThis is how you do it. NOT with an instance variable of a data context. Good job Elijah.
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