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| 如何使用 Access 2000 |
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Overview This article explains how to use Access 2000 date functions when determining 1) the number of work days representing an interval between two dates, and 2) the projected end working date calculated from a start date and number of hours worked.
The user enters in a start date and actual hours as parameters in the GetEndWorkDay function. The function calculates the date in the future the work should be completed. So, if today is 12/2/2002 and the actual hours is 12, the projected end date would be 12/3/2002.
The second part uses the GetNumberOfWorkDays function to determine what percent of the estimated time actual time represents. Estimated work days is the time interval to complete a task based on a start and end date. Comparing estimated to actual time, we can provide the percent of work completed both under or over allocated percents.
GetEndWorkDay Function
Public Function GetEndWorkDay(sStartDate, sHours) Dim iHoursToDays Dim iCount Dim bFlag Dim sEndDate Dim sCheckDate Dim iFoundCount Dim sDay
'Assume an eight hour day iHoursToDays = round(sHours / 8,0) sEndDate = sStartDate If iHoursToDays > 1 Then bFlag = False iCount = 0 iFoundCount = 0 Do While bFlag = False iCount = iCount + 1 sCheckDate = DateAdd("d", iCount, sStartDate) sDay = Weekday(sCheckDate) If sDay <> 1 And sDay <> 7 Then sEndDate = sCheckDate iFoundCount = iFoundCount + 1 End If If iFoundCount >= iHoursToDays Then Exit Do End If Loop End If GetEndWorkDay = sEndDate End Function
DateAdd returns a date to which a specific time interval has been added. In this sample the interval is "Day". List of Interval Settings: yyyy = year q = quarter m = month y = day of year d = day w = weekday ww = week h = hour n = minute s = second
Increment through a range of possible work days to find the end work date. The number of work days is determined by dividing the hours by eight. This assumes an eight hour work day. Ignore saturday and sunday as work days. Once the number of found work days equals the work day interval, stop and return the date as the final work date.
GetNumberofWorkDays Function Public Function GetNumberOfWorkDays(sStartDate, sEndDate) Dim iDays Dim iWorkDays Dim sDay Dim i
iDays = DateDiff("d", sStartDate, sEndDate)
iWorkDays = 0
For i = 0 To iDays 'First day of the week is sunday sDay = Weekday(DateAdd("d", i, sStartDate)) If sDay <> 1 And sDay <> 7 Then iWorkDays = iWorkDays + 1 End If Next GetNumberOfWorkDays = iWorkDays End Function
DateDiff specifics a number of time intervals between two dates. DateDiff (interal,date1,date2,firstdayofweek,firstweekofyear)
Interval yyyy = year q = quarter m = month y = day of year d = day w = weekday ww = week h = hour n = minute s = second date1 and date2 are used to calculate the interval firstdayofweek is sunday unless specified firstweekofyear is jan 1 unless specified
Weekday returns a number representing the day of the week.
Return values are: Sunday = 1 Monday = 2 Tuesday = 3 Wednesday = 4 Thursday = 5 Friday = 6 Saturday = 7
First determine the number of days between the two dates. Calculating the number of work days is done by not adding Saturday and Sunday dates. A query extract from a table containing all the holidays for the year could also be added for increased accuracy.
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