Here is the full recipe to retrieve single attributes from the MSSQL database:

1. Create an instance of a connection to the database, an SqlConnection object.
2. Create an instance of an SQL command, an SqlCommand object.
3. Mark the command as a stored procedure.
4. For each input parameter:
1. Create a parameter instance object.
2. Set the parameter instance object's Value parameter.
3. Add the parameter instance object to the SQL command object, created above.
5. For each output parameter:
1. Create a parameter instance object.
2. Set the parameter instance object's Direction parameter to the constant ParameterDirection.Output
3. Add the parameter instance object to the SQL command object, created above.
6. Execute the command.

Let's look at an example. The ProductsDB.js file includes the method GetProductDetail(productID: int). As its name implies, this method retrieves the details of a product with ID productID. It follows the recipe above, calling the stored procedure ProductDetail. This stored procedure expects a single input parameter, ProductID. It returns five output parameters: UnitCost, ModelNumber, ModelName, ProductImage, and Description. Here is the code:

  public function GetProductDetails(productID: int) : ProductDetails {
    var myConnection : SqlConnection = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
    var myCommand : SqlCommand = new SqlCommand("ProductDetail", myConnection);
    myCommand.CommandType = CommandType.StoredProcedure;
    var parameterProductID : SqlParameter = new SqlParameter("@ProductID", SqlDbType.Int, 4);
    parameterProductID.Value = productID;
    myCommand.Parameters.Add(parameterProductID);
    var parameterUnitCost : SqlParameter = new SqlParameter("@UnitCost", SqlDbType.Money, 8);
    parameterUnitCost.Direction = ParameterDirection.Output;
    myCommand.Parameters.Add(parameterUnitCost);
    var parameterModelNumber : SqlParameter = new SqlParameter("@ModelNumber", SqlDbType.NVarChar, 50);
    parameterModelNumber.Direction = ParameterDirection.Output;
    myCommand.Parameters.Add(parameterModelNumber);
    var parameterModelName : SqlParameter = new SqlParameter("@ModelName", SqlDbType.NVarChar, 50);
    parameterModelName.Direction = ParameterDirection.Output;
    myCommand.Parameters.Add(parameterModelName);
    var parameterProductImage : SqlParameter  = new SqlParameter("@ProductImage", SqlDbType.NVarChar, 50);
    parameterProductImage.Direction = ParameterDirection.Output;
    myCommand.Parameters.Add(parameterProductImage);
    var parameterDescription : SqlParameter  = new SqlParameter("@Description", SqlDbType.NVarChar, 3800);
    parameterDescription.Direction = ParameterDirection.Output;
    myCommand.Parameters.Add(parameterDescription);
    myConnection.Open();
    myCommand.ExecuteNonQuery();
    myConnection.Close();
    var myProductDetails : ProductDetails  = new ProductDetails();
    myProductDetails.ModelNumber = parameterModelNumber.Value;
    myProductDetails.ModelName = parameterModelName.Value;
    myProductDetails.ProductImage = (parameterProductImage.Value).Trim();
    myProductDetails.UnitCost = parameterUnitCost.Value;
    myProductDetails.Description = (parameterDescription.Value).Trim();
    return myProductDetails;
  }

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