Synchronising Google Calendar with Google Spreadsheet

[thompa]

Hi there,

I have devised a Google Spreadsheet which creates information in a
format for entry into Google Calendar.
At the moment, the Spreadsheet can be saved as a csv file for
uploading into Google Calendar.

My problem is that although the data can be imported into the
Calendar, each time that it is imported it creates new events!

If an event changes in the Spreadsheet, I should like to import the
revised events into the Calendar... erasing what was there before!

Of course it would be preferred if the Spreadsheet data could be
'shared' with the Calendar so that they are synchronised.

Allan