Quickest way to export and import data

Hi,

We have been using DataExtract to save our data and then import it again.

Unfortunately now that we have gone up to 1 million records in a table, it
takes 45 mins to do the import!

I know there are various ways to do this - what is the **quickest** and
most efficient?  What kind of speed can I expect in this case?

many thanks,

David