Best approach to write huge xml data to file?

I'm currently exporting a database table with huge data (100000+ records) into an xml file using XmlTextWriter class and I'm writing directly to a file on the physical drive.

_XmlTextWriterObject = new XmlTextWriter(_xmlFilePath, null);

While my code runs ok, my question is that is it the best approach? Should I instead write the whole xml in memory stream first and then write the xml document in physical file from memory stream? And what are the effects on memory/ performance in both cases?

EDIT

Sorry that I could not actually convey what I meant to say.Thanks Ash for pointing out. I will indeed be using XmlTextWriter but I meant to say whether to pass a physical file path string to the XmlTextWriter constructor (or, as John suggested, to the XmlTextWriter.Create() method) or use stream based api. My current code looks like the following:

XmlWriter objXmlWriter = XmlTextWriter.Create(new BufferedStream(new FileStream(@"C:\test.xml", FileMode.Create, System.Security.AccessControl.FileSystemRights.Write, FileShare.None, 1024, FileOptions.SequentialScan)), new XmlWriterSettings { Encoding = Encoding.Unicode, Indent = true, CloseOutput = true });
using (objXmlWriter)
{
   //writing xml contents here
}

Solution

While my code runs ok, my question is that is it the best approach?

As mentioned and your update, XmlWriter.Create is fine.

Or should I write the whole xml in memory stream first and then write the xml document in physical file from memory stream?

Do you have the memory to write the entire file in-memory? If you do then that approach will be faster, otherwise stream it using a FileStream which will take care of it for you.

And what are the effects on memory/ performance in both cases?

Reading the entire XML file in will use more memory, and spike the processor to start with. Streaming to disk will use more processor. But you'll need to be using a huge file for this to be noticeable given even desktop hardware now. If you're worried about the size increasing even more in the future, stick to the FileStream technique to future proof it.