DataTable.Select and Performance Issue in C#

Question

Hi All, I'm importing the data from three Tab delimited files in the DataTables and after that I need to go thru every row of master table and find all the rows in two child tables. Against each DataRow[] array I found from the child tables, I have to again go thru individually each row and check the values based upon different paramenters and at the end I need to create a final record which will be merger of master and two child table columns. Now I have done that and its working but the problem is its Performance. I'm using the DataTable.Select to find all child rows from child table which I believe making it very slow. Please remember the None of the table has any Primary key as the duplicate rows are acceptable. At the moment I have 1200 rows in master table and aroun 8000 rows in child table and the total time it takes to do that is 8 minutes.

Any idea how can I increase the Performance. Thanks in advance

The code is below *******

 DataTable rawMasterdt = importMasterFile();
 DataTable rawDespdt = importDescriptionFile();

        dsHelper = new DataSetHelper();
        DataTable distinctdt = new DataTable();
        distinctdt = dsHelper.SelectDistinct("DistinctOffers", rawMasterdt, "C1");

        if (distinctdt.Rows.Count > 0)
        {
            int count = 0;
                foreach (DataRow offer in distinctdt.Rows)
                {
                    string exp = "C1 = " + "'" + offer[0].ToString() + "'" + "";
                    DataRow masterRow = rawMasterdt.Select(exp)[0];

                    count++;
                    txtBlock1.Text = "Importing Offer " + count.ToString() + " of " + distinctdt.Rows.Count.ToString(); 
                    if (masterRow != null )
                        {
                            Product newProduct = new Product();

                            newProduct.Code = masterRow["C4"].ToString();
                            newProduct.Name = masterRow["C5"].ToString();
                          //  -----
                            newProduct.Description = getProductDescription(offer[0].ToString(), rawDespdt);
                            newProduct.Weight = getProductWeight(offer[0].ToString(), rawDespdt);
                            newProduct.Price = getProductRetailPrice(offer[0].ToString(), rawDespdt);
                            newProduct.UnitPrice = getProductUnitPrice(offer[0].ToString(), rawDespdt);
                          //  ------- more functions similar to above here

                            productList.Add(newProduct);
                        }
                }
                txtBlock1.Text = "Import Completed";
 public string getProductDescription(string offercode, DataTable dsp)
    {
        string exp = "((C1 = " + "'" + offercode + "')" + " AND ( C6 = 'c' ))";
        DataRow[] dRows = dsp.Select( exp);
        string descrip = "";
        if (dRows.Length > 0)
        { 
            for (int i = 0; i < dRows.Length - 1; i++)
            {
              descrip = descrip + " " + dRows[i]["C12"];
            }
        }
        return descrip;

    }

Answer 1

DataTables can be made to have Relationships with other DataTables in a DataSet. See http://msdn.microsoft.com/en-us/library/ay82azad%28VS.71%29.aspx for a bit of discussion and as a start point to browsing. I've not much experience of using them but as I understand it they will do what you want (assuming your tables are in a suitable format). I would assume that these have greater efficiency than a manual process of doing the same but I may be wrong. Might be worth seeing if they work for you and benchmarking to see if they are an improvement or not...