Question

i have managed to connect to an interbase database and get data from the database and store it in a dataset, i need to manipulate some of the data in the dataset and do something like the following,

add a new column in the dataset called total,
for each row i need to add the 2nd and 3rd column and place the result into the total column.

can some one shed some light on how i may do this, im using the following code to get the data into a data set.

    OdbcConnection conn = new OdbcConnection();
    conn.ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString2"].ConnectionString;

    DataSet ds = new DataSet();

    OdbcDataAdapter da = new OdbcDataAdapter("SELECT * FROM MTD_FIGURE_VIEW1", conn);

    da.Fill(ds);

Answer 1

IF you are sure that your column values would never be null or empty then the best way is

ds.Tables[0].Columns.Add("Sum", typeof(double), "Col1 + Col2");

In case if your any column’s value will be null then it wont give any exception but the total value would also be empty …

If there can be any null value then try this

           dt.Columns.Add("Total", typeof(double));
        foreach (DataRow dr in dt.Rows)
        {
            if (String.IsNullOrEmpty(dr["col1"].ToString()))
                dr["col1"] = 0.0;
            if (String.IsNullOrEmpty(dr["col2"].ToString()))
                dr["col2"] = 0.0;

            dr["Total"] = Convert.ToDouble(dr["col1"]) + Convert.ToDouble(dr["col2"]);
        }

In this case if you never check for null or empty value then this will give you a run time exception…