CSharp reading data from Access Database using oledbdatareader


I am writing some in code in C# which retrieves data from an Access database (please see it below). According to some of the articles on the internet there is no count property for oledbdatareader. I know you can query the number & then run the query again but I do not wish to do this as the query takes a while already without running it twice. Is there a better way to query data from an access database (or SQL Server going forward) than how I have done it below & where I am also able to count the number records returned.


OleDbConnection dbConnection = new OleDbConnection(cn + dbPath + "dbFX_1Min_db.mdb");

            OleDbCommand SQLQuery = dbConnection.CreateCommand();

            SQLQuery.CommandText= @"SELECT [Plot_PriceData].[DTime], [Plot_PriceData].[Close], [Plot_PriceData].[Signal]
                                    FROM [Plot_PriceData]
                                    WHERE ((([Plot_PriceData].[Pair])='" + Security + @"') 
                                    AND (([Plot_PriceData].[DTime])>=#" + dtFrom + @"# 
                                    And ([Plot_PriceData].[DTime])<=#" + dtTo + @"#))
                                    ORDER BY [Plot_PriceData].[DTime];";
            OleDbDataReader PriceReader = SQLQuery.ExecuteReader();

            if (PriceReader.HasRows)
                while (PriceReader.Read())
                    Element priceElement = new Element();

                    priceElement.XDateTime = (DateTime)PriceReader["DTime"];
                    priceElement.YValue = (Double)PriceReader["Close"];

                        if ((string)PriceReader["Signal"]=="B")
                            priceElement.Annotation = new Annotation();
                            priceElement.SmartLabel.Alignment = LabelAlignment.Bottom;
                        else if((string)PriceReader["Signal"] =="S")
                            priceElement.Annotation = new Annotation();                            
                            priceElement.SmartLabel.Alignment = LabelAlignment.Top;



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käµfm³d 👽Commented:
If the data being returned is not terribly large, you can load it into a DataTable. Then you would have access to a Count property on the rows:

DataTable dt = new DataTable();

int rowCount = dt.Rows.Count;

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mcs26Author Commented:
Hi Kaufmed,

More often than not the number of rows will be 100,000 with 11 fields although pontentially it could also be 1million. Would that be ok to use a DataTable?

If it is to large for a DataTable what would you adivse?

käµfm³d 👽Commented:
I believe the 100,000 would be OK, but the 1,000,000, maybe not.

On second thought, can you not have a counter variable defined outside of the loop? For each call to Read, increment the variable.

if (PriceReader.HasRows)
        int rowCount = 0;

        while (PriceReader.Read())


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käµfm³d 👽Commented:
Side note:  Your call to PriceReader.HasRows in this case is redundant. If you call PriceReader.Read the first time and it returns false, then there are no rows.
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