[AccessD] Dates as Rata Die

Hi all

Not a Friday joke, but did you know about the Rata Die numbering system for dates:

  http://en.wikipedia.org/wiki/Rata_Die 

However, these are quite easy to handle in Access:

<code>

Public Function DateFromRataDie(ByVal lngRataDie As Long) As Date

' Converts a date as Rata Die value to its date/time value.
' Rata Die is the count of days since 0001-01-01 00:00:00 UTC
'
' Zero value of Rata Die is 0001-01-01 00:00:00 UTC
' Offset in relation to the date of zero value of VB(A) date/time value
' is the year of date/time numeric value zero.
'
' 2009-02-06. Cactus Data ApS. CPH.

  Const datZero     As Date = #12:00:00 AM#
  Dim datDate       As Date
  
  datDate = DateAdd("yyyy", -Year(datZero), DateAdd("d", lngRataDie, datZero))
  
  DateFromRataDie = datDate
  
End Function

Public Function DateToRataDie(ByVal datDate As Date) As Long

' Converts a date/time value to its Rata Die value.
' Rata Die is the count of days since 0001-01-01 00:00:00 UTC
'
' Zero value of Rata Die is 0001-01-01 00:00:00 UTC
' Offset in relation to the date of zero value of VB(A) date/time value
' is the year of date/time numeric value zero.
'
' 2009-02-06. Cactus Data ApS. CPH.

  Const datZero     As Date = #12:00:00 AM#
  Dim lngRataDie    As Long
  
  lngRataDie = DateDiff("d", datZero, DateAdd("yyyy", Year(datZero), datDate))
  
  DateToRataDie = lngRataDie

End Function

</code>

/gustav