I have a table with 10,000 records but I only want to read 250 at a time. I know the row number of the 250 records that I have to read and so I want to avoid reading all 100,000 records each time. For example, if I want to read rows 60,001 to 60,250 how would I do that? Is there any way of doing it without reading the previous 60,000 rows?

Below is my code:

public class cRead_CoveringElementType_Variation_IntoArray

    public static void mRead_CoveringElementType_Varation_IntoArray(int liFromBlock, int liToBlock)

        int liRowNo = 0;
        int liMiscLp = 0;

        string strCommSelect = "";

        strCommSelect = "SELECT * FROM tbl_COVERING_and_KType";

        string strConnection = @"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\CombinatoRoyX\DataBase\dbCoveringType_Sorted.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True"; // User Id=sa;Password=Elena_501_Pogutz; This is the PW
        SqlConnection oConnection = new SqlConnection(strConnection);
        SqlCommand oCommand = new SqlCommand(strCommSelect, oConnection);


        SqlDataReader mySqlDataReader = oCommand.ExecuteReader();

        int liRowToRead = 0;

        while (mySqlDataReader.Read())
            if (liRowNo >= liFromBlock && liRowNo <= liToBlock)


                for (liMiscLp = 1; liMiscLp <= 2 * aGV.K; liMiscLp++) aGV.Cov_Var[liRowToRead, liMiscLp] = mySqlDataReader.GetInt32(liMiscLp);





Edited by Ezzaral: Fixed code tags.

7 Years
Discussion Span
Last Post by sknake

Please make sure to use matching code tags when posting code:

[code=C#] ...code...


You should modify your query to only select the desired records. MSSQL has a hard limit of 2100 parameters. As far as selecting rows #N1-N2 you have a few options.

#1 - Parameters:

Select * From dbo.[Table] Where [Table].[RowNumber] In (@P1, @P2, @P3)
DataTable GetRows()
      using (SqlConnection conn = new SqlConnection("conn string"))
        using (SqlCommand cmd = conn.CreateCommand())
          cmd.CommandText = @"Select * From dbo.[Table] Where [Table].[RowNumber] In (@P1, @P2, @P3)";
          cmd.Parameters.Add("@P1", SqlDbType.Int).Value = 1;
          cmd.Parameters.Add("@P2", SqlDbType.Int).Value = 2;
          cmd.Parameters.Add("@P3", SqlDbType.Int).Value = 3;
          using (SqlDataReader dr = cmd.ExecuteReader())
            DataTable dt = new DataTable();
            return dt;

#2 - No Parameters:

Select * From dbo.[Table] Where [Table].[RowNumber] In (1, 2, 3)

There are a few TSQL tricks to assign row numbers if your schema doesn't support selecting forth the desired rows.

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