How to get right refrences for the SqlCommand and SqlConnection in visual studio express for windows phone

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C#

Windows

Visual-Studio

database

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Hi I am developing a windows phone application in visual studio express for windows phone. My problem is that when I am using SqlCommand an SqlConncetion I get a reference fault:
type or namespace name 'SqlCommand' could not be found (are you missing a using directive or an assmbly refrence)

When I try to add a using system.data.sql; it will not recognice this command or others related to this. How do I go about fixing this issue ?

private void button1_Click(object sender, RoutedEventArgs e)
{
   SqlCommand test = new SqlCommand();
}