Hello,
I am using the following code to perform calculation of "Work Days" rather than calendar days between two dates. I have around a million rows at maximum, and the current design of this causes the Max Locking error, and when isolated into smaller chunks of data (10k), it still runs very slow.
Any way to change things up so that it is more efficient? (I am experienced w/ Access, but usually rely on finding bits of VBA from others, as I learn it)
(I think the first function calls the second one)
Code:
Option Compare DatabaseOption Explicit
Public Function Workdays(ByRef startDate As Date, _
ByRef endDate As Date, _
Optional ByRef strHolidays As String = "Holidays" _
) As Integer
' Returns the number of workdays between startDate
' and endDate inclusive. Workdays excludes weekends and
' holidays. Optionally, pass this function the name of a table
' or query as the third argument. If you don't the default
' is "Holidays".
On Error GoTo Workdays_Error
Dim nWeekdays As Integer
Dim nHolidays As Integer
Dim strWhere As String
' DateValue returns the date part only.
startDate = DateValue(startDate)
endDate = DateValue(endDate)
nWeekdays = Weekdays(startDate, endDate)
If nWeekdays = -1 Then
Workdays = -1
GoTo Workdays_Exit
End If
strWhere = "[Holiday] >= #" & startDate _
& "# AND [Holiday] <= #" & endDate & "#"
' Count the number of holidays.
nHolidays = DCount(Expr:="[Holiday]", _
Domain:=strHolidays, _
Criteria:=strWhere)
Workdays = nWeekdays - nHolidays
Workdays_Exit:
Exit Function
Workdays_Error:
Workdays = -1
MsgBox "Error " & Err.Number & ": " & Err.Description, _
vbCritical, "Workdays"
Resume Workdays_Exit
End Function
Public Function Weekdays(ByRef startDate As Date, _
ByRef endDate As Date _
) As Integer
' Returns the number of weekdays in the period from startDate
' to endDate inclusive. Returns -1 if an error occurs.
' If your weekend days do not include Saturday and Sunday and
' do not total two per week in number, this function will
' require modification.
On Error GoTo Weekdays_Error
' The number of weekend days per week.
Const ncNumberOfWeekendDays As Integer = 2
' The number of days inclusive.
Dim varDays As Variant
' The number of weekend days.
Dim varWeekendDays As Variant
' Temporary storage for datetime.
Dim dtmX As Date
' If the end date is earlier, swap the dates.
If endDate < startDate Then
dtmX = startDate
startDate = endDate
endDate = dtmX
End If
' Calculate the number of days inclusive (+ 1 is to add back startDate).
varDays = DateDiff(Interval:="d", _
date1:=startDate, _
date2:=endDate) + 1
' Calculate the number of weekend days.
varWeekendDays = (DateDiff(Interval:="ww", _
date1:=startDate, _
date2:=endDate) _
* ncNumberOfWeekendDays) _
+ IIf(DatePart(Interval:="w", _
Date:=startDate) = vbSunday, 1, 0) _
+ IIf(DatePart(Interval:="w", _
Date:=endDate) = vbSaturday, 1, 0)
' Calculate the number of weekdays.
Weekdays = (varDays - varWeekendDays)
Weekdays_Exit:
Exit Function
Weekdays_Error:
Weekdays = -1
MsgBox "Error " & Err.Number & ": " & Err.Description, _
vbCritical, "Weekdays"
Resume Weekdays_Exit
End Function