Loading Data Into a DataSet

A DataSet object must first be populated before you can query over it with LINQ to DataSet. There are several different ways to populate the DataSet. For example, you can use LINQ to SQL to query the database and load the results into the DataSet. For more information, see LINQ to SQL.

Another common way to load data into a DataSet is to use the DataAdapter class to retrieve data from the database. This is illustrated in the following example.

Example

This example uses a DataAdapter to query the AdventureWorks database for sales information from the year 2002, and loads the results into a DataSet. After the DataSet has been populated, you can write queries against it by using LINQ to DataSet. The FillDataSet method in this example is used in the example queries in LINQ to DataSet Examples. For more information, see Querying DataSets (LINQ to DataSet).

try

{
    // Create a new adapter and give it a query to fetch sales order, contact, 
    // address, and product information for sales in the year 2002. Point connection 
    // information to the configuration setting "AdventureWorks".
    string connectionString = "Data Source=localhost;Initial Catalog=AdventureWorks;"
        + "Integrated Security=true;";


    SqlDataAdapter da = new SqlDataAdapter(
        "SELECT SalesOrderID, ContactID, OrderDate, OnlineOrderFlag, " +
        "TotalDue, SalesOrderNumber, Status, ShipToAddressID, BillToAddressID " +
        "FROM Sales.SalesOrderHeader " +
        "WHERE DATEPART(YEAR, OrderDate) = @year; " +

        "SELECT d.SalesOrderID, d.SalesOrderDetailID, d.OrderQty, " +
        "d.ProductID, d.UnitPrice " +
        "FROM Sales.SalesOrderDetail d " +
        "INNER JOIN Sales.SalesOrderHeader h " +
        "ON d.SalesOrderID = h.SalesOrderID  " +
        "WHERE DATEPART(YEAR, OrderDate) = @year; " +

        "SELECT p.ProductID, p.Name, p.ProductNumber, p.MakeFlag, " +
        "p.Color, p.ListPrice, p.Size, p.Class, p.Style, p.Weight  " +
        "FROM Production.Product p; " +

        "SELECT DISTINCT a.AddressID, a.AddressLine1, a.AddressLine2, " +
        "a.City, a.StateProvinceID, a.PostalCode " +
        "FROM Person.Address a " +
        "INNER JOIN Sales.SalesOrderHeader h " +
        "ON  a.AddressID = h.ShipToAddressID OR a.AddressID = h.BillToAddressID " +
        "WHERE DATEPART(YEAR, OrderDate) = @year; " +

        "SELECT DISTINCT c.ContactID, c.Title, c.FirstName, " +
        "c.LastName, c.EmailAddress, c.Phone " +
        "FROM Person.Contact c " +
        "INNER JOIN Sales.SalesOrderHeader h " +
        "ON c.ContactID = h.ContactID " +
        "WHERE DATEPART(YEAR, OrderDate) = @year;",
    connectionString);

    // Add table mappings.
    da.SelectCommand.Parameters.AddWithValue("@year", 2002);
    da.TableMappings.Add("Table", "SalesOrderHeader");
    da.TableMappings.Add("Table1", "SalesOrderDetail");
    da.TableMappings.Add("Table2", "Product");
    da.TableMappings.Add("Table3", "Address");
    da.TableMappings.Add("Table4", "Contact");

    // Fill the DataSet.
    da.Fill(ds);

    // Add data relations.
    DataTable orderHeader = ds.Tables["SalesOrderHeader"];
    DataTable orderDetail = ds.Tables["SalesOrderDetail"];
    DataRelation order = new DataRelation("SalesOrderHeaderDetail",
                             orderHeader.Columns["SalesOrderID"],
                             orderDetail.Columns["SalesOrderID"], true);
    ds.Relations.Add(order);

    DataTable contact = ds.Tables["Contact"];
    DataTable orderHeader2 = ds.Tables["SalesOrderHeader"];
    DataRelation orderContact = new DataRelation("SalesOrderContact",
                                    contact.Columns["ContactID"],
                                    orderHeader2.Columns["ContactID"], true);
    ds.Relations.Add(orderContact);
}
catch (SqlException ex)
{
    Console.WriteLine("SQL exception occurred: " + ex.Message);
}

ref : http://msdn.microsoft.com/en-us/library/bb399340.aspx