How to learn ADO.NET

I need to learn ADO.NET to build applications based on MS Office. I have read a good deal about ADO.NET in the MSDN Library, but everything seems rather messy to me.

What's the basics one must figure out when using ADO.NET? I think a few key words will suffice to let me organize my learning.

From stackoverflow $pageUsers[$entry.posts[0].author].name

• There are three key components (assuming ur using SQL server):

  SQLConnection, SqlCommand, SqlDataReader

  (if you're using something else, replace "Sql" with "Something", like "MySqlConnection", "OracleCommand"

  Everything else is just built on top of that Example 1:

  using (SqlConnection connection = new SqlConnection("CONNECTION STRING"))
  using (SqlCommand command = new SqlCommand())
  {
    command.commandText = "SELECT Name FROM Users WHERE Status = @OnlineStatus";
    command.Connection = connection;
    command.Parameters.Add("@OnlineStatus", SqlDbType.Int).Value = 1; //replace with enum
    connection.Open();
    using (SqlDataReader dr = command.ExecuteReader))
    {
        List<string> onlineUsers = new List<string>();
        while (dr.Read())
        {
           onlineUsers.Add(dr.GetString(0));
        }
    }
  }
  

  Example 2:

  using (SqlConnection connection = new SqlConnection("CONNECTION STRING"))
  using (SqlCommand command = new SqlCommand())
  {
    command.commandText = "DELETE FROM Users where Email = @Email";
    command.Connection = connection;
    command.Parameters.Add("@Email", SqlDbType.VarChar, 100).Value = "user@host.com";
    connection.Open();
    command.ExecuteNonQuery();
  }
  

  From Karl Seguin

• Another way of gettinga command object is to call "connection.CreateCommand()". That way you shouldn't have to set the Commection property on the command object.

  From Mark Cidade