Importing external data with specific time format into MS Access

Question

I need to import data from a flat file to MS Access. Part of the data is time information in the format HH:MM:SS.SSSS (i.e. 24-hour time, fractional seconds). I have tried all of the standard time formats, and have monkeyed around with input masking, but Access keeps complaining that I am violating formats and won't import my data. Anybody know how to do this? Thanks.

(BTW, the "date-format" tag was the closest I could find to something like "time format".)

• AA.SC: Bob did you tried to import that time information as text from flat file? is this file is CSV?
• bob.sacamento: @AA.SC Yes. I tried to import from a text flat file. The fields are delimited by tabs. I actually found on another site a comment from an MS engineer to the effect that MS Access time format simply doesn't allow fractional seconds. So I put all the integers into the time and split off the fractional part of the seconds into a separate field. Kind of ugly, but I haven't thought of a better way. Ideas are appreciated!
• Gord Thompson: It's true, the Date/Time column type in Access does not support fractional seconds. Do you need to keep that degree of precision or would rounding to the nearest second suffice?
• Yawar: One thing I've found is that when importing data from text files, Access uses roughly the first 100 rows of data to build up a preview of what it should expect from the entire file. If your first 100 rows contain all possible variations of the time column, that gives Access a better chance of reading it right.
• bob.sacamento: @Gord Thompson I don't need all the precision given but, no, rounding wouldn't be close enough. Thanks for the idea.

Answer 1

As you have discovered, the Date/Time column type in Access does not support fractional seconds. If you need to preserve the precision (and not round to the nearest second) then you'll need to import the time values as Text and then populate another Long Integer column with the times converted to tenths-of-milliseconds (which I have abbreviated to "tms"):

After the initial import of the times as Text you will have something like this

ID hms_time tms_time 
-- ------------- ---------
 1 00:00:00.0001
 2 23:59:59.9999
 3 00:00:00.0000
 4 03:25:45.6789
 5 22:57:40.0000

If you create a VBA function in an Access Module like this

Option Compare Database
Option Explicit
Public Function Hms2Tms(hms As Variant) As Variant
 ' convert "hh:mm:ss.dddd" String
 ' to Long Integer tenths-of-milliseconds (0..863999999)
 Dim arr() As String, rtn As Long
 If IsNull(hms) Then
 Hms2Tms = Null
 Else
 arr = Split(hms, ":", -1, vbBinaryCompare)
 rtn = CLng(arr(0)) * 36000000 + CLng(arr(1)) * 600000
 arr = Split(arr(2), ".", 2, vbBinaryCompare)
 rtn = rtn + CLng(arr(0)) * 10000 + CLng(arr(1))
 Hms2Tms = rtn
 End If
End Function

then you can use the query

UPDATE TimesTable SET tms_time = Hms2Tms([hms_time])

to calculate the numeric equivalents

ID hms_time tms_time 
-- ------------- ---------
 1 00:00:00.0001 1
 2 23:59:59.9999 863999999
 3 00:00:00.0000 0
 4 03:25:45.6789 123456789
 5 22:57:40.0000 826600000

You can also use the following VBA function to convert a numeric "tms" time into an "hms" string:

Public Function Tms2Hms(tms As Variant) As Variant
 ' convert Long Integer tenths-of-milliseconds (0..863999999)
 ' to "hh:mm:ss.dddd" String
 Dim hh As Long, mm As Long, ss_dddd As Currency, remainder As Long, rtn As String
 If IsNull(tms) Then
 Tms2Hms = Null
 Else
 hh = Int(CCur(tms) / 36000000)
 rtn = Format(hh, "00")
 remainder = tms - hh * 36000000
 mm = Int(CCur(remainder) / 600000)
 rtn = rtn & ":" & Format(mm, "00")
 remainder = remainder - mm * 600000
 ss_dddd = CCur(remainder) / 10000
 rtn = rtn & ":" & Format(ss_dddd, "00.0000")
 Tms2Hms = rtn
 End If
End Function