How to efficiently write to file from SQL datareader in c#?

Question

I have a remote sql connection in C# that needs to execute a query and save its results to the users\'s local hard disk. There is a fairly large amount of data this thing ca

Answer 1

You are on the right track yourself. Use a loop with while(myReader.Read(){...} and write each record to the text file inside the loop. The .NET framework and operating system will take care of flushing the buffers to disk in an efficient way.

using(SqlConnection conn = new SqlConnection(connectionString))
using(SqlCommand cmd = conn.CreateCommand())
{
  conn.Open();
  cmd.CommandText = QueryLoader.ReadQueryFromFileWithBdateEdate(
    @"Resources\qrs\qryssysblo.q", newdate, newdate);

  using(SqlDataReader reader = cmd.ExecuteReader())
  using(StreamWriter writer = new StreamWriter("c:\temp\file.txt"))
  {
    while(reader.Read())
    {
      // Using Name and Phone as example columns.
      writer.WriteLine("Name: {0}, Phone : {1}", 
        reader["Name"], reader["Phone"]);
    }
  }
}