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Concurrency violation and DateTimeI’m trying to design a front end program in VB.NET for a MS Access database.
I’m getting Concurrency Violation errors when updating if there is a DateTime field in my table that has been edited in Access. Seems to be when there is a Time value in the column. This is even happening from forms generated by the Data Form Wizard, so I don't think its code I'm writing. What am I missing here? Jim,
> I'm trying to design a front end program in VB.NET for a MS Access If somebody else has in the meantime that your program is busy changed any > database. > I'm getting Concurrency Violation errors when updating if there is a > DateTime > field in my table that has been edited in Access. Seems to be when there > is a > Time value in the column. > field that is in your datatable using MS - Access and you want to update that, than that means a connurrency violation in the standard procedures of the OleDbDataadapter. It checks if the old value is the same as it it was when read. Cor This is happening when my VB.net program is the only user of the
database. The Time values seem to be different between Access and VB. If I clear the date or put in just mm/dd/yyyy values everything is fine. However when in production one of the DateTime fields needs to be a full mm/dd/yyyy hh:nn:ss value. Also both the Access and VB program would be in use, hense my problem. On Wed, 21 Jun 2006 07:07:20 +0200, "Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote: Show quote >Jim, > >> I'm trying to design a front end program in VB.NET for a MS Access >> database. >> I'm getting Concurrency Violation errors when updating if there is a >> DateTime >> field in my table that has been edited in Access. Seems to be when there >> is a >> Time value in the column. >> >If somebody else has in the meantime that your program is busy changed any >field that is in your datatable using MS - Access and you want to update >that, than that means a connurrency violation in the standard procedures of >the OleDbDataadapter. It checks if the old value is the same as it it was >when read. > >Cor > Jim,
Yes the time and dates between Access and VB can be fractional different in the milleseconds part. However I don't see how this can affect your problem. Can you show us a piece of code where you handle the datetime. Cor Show quote "Jim Brown" <j*@applicationsplus.com> schreef in bericht news:2e9i92din6a3rafh342lndsftr9vpe0o35@4ax.com... > This is happening when my VB.net program is the only user of the > database. > > The Time values seem to be different between Access and VB. If I clear > the date or put in just mm/dd/yyyy values everything is fine. However > when in production one of the DateTime fields needs to be a full > mm/dd/yyyy hh:nn:ss value. Also both the Access and VB program would > be in use, hense my problem. > > On Wed, 21 Jun 2006 07:07:20 +0200, "Cor Ligthert [MVP]" > <notmyfirstn***@planet.nl> wrote: > >>Jim, >> >>> I'm trying to design a front end program in VB.NET for a MS Access >>> database. >>> I'm getting Concurrency Violation errors when updating if there is a >>> DateTime >>> field in my table that has been edited in Access. Seems to be when there >>> is a >>> Time value in the column. >>> >>If somebody else has in the meantime that your program is busy changed any >>field that is in your datatable using MS - Access and you want to update >>that, than that means a connurrency violation in the standard procedures >>of >>the OleDbDataadapter. It checks if the old value is the same as it it was >>when read. >> >>Cor >> Not sure, but I've seen something similar caused by optimistic locking when
the server side and client side precision doesn't match for datetime values. The scenario is : - a datetime value is retrieved from the DB - as the precision is bigger than the client side precision, it is truncated - the where clause used for optimistic locking can' t find the original row as the datetime value was truncated. This is seen as if someone else changed the record. It was with SQL Server/ADO but it looks like it could be something similar with Access/ADO.NET. See the statement used by the adapter, the original value kept by the application and double check you have the same value in your Access DB (be aware also of the format that could prevent to see the whole field if you see the DB using the Access UI). -- Patrice "Jim Brown" <j*@applicationsplus.com> a écrit dans le message de news: 2e9i92din6a3rafh342lndsftr9vpe0***@4ax.com...Show quote > This is happening when my VB.net program is the only user of the > database. > > The Time values seem to be different between Access and VB. If I clear > the date or put in just mm/dd/yyyy values everything is fine. However > when in production one of the DateTime fields needs to be a full > mm/dd/yyyy hh:nn:ss value. Also both the Access and VB program would > be in use, hense my problem. > > On Wed, 21 Jun 2006 07:07:20 +0200, "Cor Ligthert [MVP]" > <notmyfirstn***@planet.nl> wrote: > >>Jim, >> >>> I'm trying to design a front end program in VB.NET for a MS Access >>> database. >>> I'm getting Concurrency Violation errors when updating if there is a >>> DateTime >>> field in my table that has been edited in Access. Seems to be when there >>> is a >>> Time value in the column. >>> >>If somebody else has in the meantime that your program is busy changed any >>field that is in your datatable using MS - Access and you want to update >>that, than that means a connurrency violation in the standard procedures >>of >>the OleDbDataadapter. It checks if the old value is the same as it it was >>when read. >> >>Cor >> To add to Patrice,
I never noticed this but maybe is it something that the date is given as Now somewhere. The DateTime in Net is accurate to100 nanoseconds, in Access it is accurate to 1000/3 milliseconds. Cor Show quote "Patrice" <scr***@chez.com> schreef in bericht news:%23WsPcTTlGHA.2112@TK2MSFTNGP04.phx.gbl... > Not sure, but I've seen something similar caused by optimistic locking > when the server side and client side precision doesn't match for datetime > values. > > The scenario is : > - a datetime value is retrieved from the DB > - as the precision is bigger than the client side precision, it is > truncated > - the where clause used for optimistic locking can' t find the original > row as the datetime value was truncated. This is seen as if someone else > changed the record. > > It was with SQL Server/ADO but it looks like it could be something similar > with Access/ADO.NET. > > See the statement used by the adapter, the original value kept by the > application and double check you have the same value in your Access DB (be > aware also of the format that could prevent to see the whole field if you > see the DB using the Access UI). > > -- > Patrice > > "Jim Brown" <j*@applicationsplus.com> a écrit dans le message de news: > 2e9i92din6a3rafh342lndsftr9vpe0***@4ax.com... >> This is happening when my VB.net program is the only user of the >> database. >> >> The Time values seem to be different between Access and VB. If I clear >> the date or put in just mm/dd/yyyy values everything is fine. However >> when in production one of the DateTime fields needs to be a full >> mm/dd/yyyy hh:nn:ss value. Also both the Access and VB program would >> be in use, hense my problem. >> >> On Wed, 21 Jun 2006 07:07:20 +0200, "Cor Ligthert [MVP]" >> <notmyfirstn***@planet.nl> wrote: >> >>>Jim, >>> >>>> I'm trying to design a front end program in VB.NET for a MS Access >>>> database. >>>> I'm getting Concurrency Violation errors when updating if there is a >>>> DateTime >>>> field in my table that has been edited in Access. Seems to be when >>>> there >>>> is a >>>> Time value in the column. >>>> >>>If somebody else has in the meantime that your program is busy changed >>>any >>>field that is in your datatable using MS - Access and you want to update >>>that, than that means a connurrency violation in the standard procedures >>>of >>>the OleDbDataadapter. It checks if the old value is the same as it it was >>>when read. >>> >>>Cor >>> > > On Tue, 20 Jun 2006 12:23:02 -0700, Jim Brown <j*@applicationsplus.com.(donotspam)> wrote:
¤ I’m trying to design a front end program in VB.NET for a MS Access database. ¤ I’m getting Concurrency Violation errors when updating if there is a DateTime ¤ field in my table that has been edited in Access. Seems to be when there is a ¤ Time value in the column. ¤ ¤ This is even happening from forms generated by the Data Form Wizard, so I ¤ don't think its code I'm writing. ¤ ¤ What am I missing here? Check the parameter type for this column generated by the DataAdapter. It might be System.Data.OleDb.OleDbType.DBDate but it should be System.Data.OleDb.OleDbType.Date. Paul ~~~~ Microsoft MVP (Visual Basic) Where do I go to check that in Visual development program and can it
be changed? On Wed, 21 Jun 2006 08:11:44 -0500, Paul Clement <UseAdddressAtEndofMess***@swspectrum.com> wrote: Show quote >On Tue, 20 Jun 2006 12:23:02 -0700, Jim Brown <j*@applicationsplus.com.(donotspam)> wrote: > >¤ I’m trying to design a front end program in VB.NET for a MS Access database. >¤ I’m getting Concurrency Violation errors when updating if there is a DateTime >¤ field in my table that has been edited in Access. Seems to be when there is a >¤ Time value in the column. >¤ >¤ This is even happening from forms generated by the Data Form Wizard, so I >¤ don't think its code I'm writing. >¤ >¤ What am I missing here? > >Check the parameter type for this column generated by the DataAdapter. It might be >System.Data.OleDb.OleDbType.DBDate but it should be System.Data.OleDb.OleDbType.Date. > > >Paul >~~~~ >Microsoft MVP (Visual Basic) On Thu, 22 Jun 2006 11:28:31 -0400, Jim Brown <j*@applicationsplus.com> wrote:
¤ Where do I go to check that in Visual development program and can it ¤ be changed? ¤ If you're working with VS 2003 try searching for DBDate. You should find it in the Windows Form Designer Region. Paul ~~~~ Microsoft MVP (Visual Basic) You were right. In the "Windows Form Designer" code region I found
where my dates are defined as DBDATE's rather that DATE's which would keep the time values? So the code generator for my version 2002 VB.NET was not right. Any idea about the new 2005 version? On Thu, 22 Jun 2006 13:37:30 -0500, Paul Clement <UseAdddressAtEndofMess***@swspectrum.com> wrote: Show quote >On Thu, 22 Jun 2006 11:28:31 -0400, Jim Brown <j*@applicationsplus.com> wrote: > >¤ Where do I go to check that in Visual development program and can it >¤ be changed? >¤ > >If you're working with VS 2003 try searching for DBDate. You should find it in the Windows Form >Designer Region. > > >Paul >~~~~ >Microsoft MVP (Visual Basic) On Sat, 24 Jun 2006 17:48:49 -0400, Jim Brown <j*@applicationsplus.com> wrote:
¤ You were right. In the "Windows Form Designer" code region I found ¤ where my dates are defined as DBDATE's rather that DATE's which would ¤ keep the time values? ¤ ¤ So the code generator for my version 2002 VB.NET was not right. Any ¤ idea about the new 2005 version? ¤ Yes, I believe this was fixed in the 2005 version. Paul ~~~~ Microsoft MVP (Visual Basic) You may want to look into DateTime.ToOADate for use in your VB.Net program.
http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/VB_DOT_NET/Q_21538974.html has a discussion that I beleive is relevant. Show quote "Jim Brown" <j*@applicationsplus.com.(donotspam)> wrote in message news:E8AB3280-E2A2-4C4D-AD8D-6E9C8D900F07@microsoft.com... > I'm trying to design a front end program in VB.NET for a MS Access > database. > I'm getting Concurrency Violation errors when updating if there is a > DateTime > field in my table that has been edited in Access. Seems to be when there > is a > Time value in the column. > > This is even happening from forms generated by the Data Form Wizard, so I > don't think its code I'm writing. > > What am I missing here? > I am wondering if this can be related to conversion to/from UTC time
somehow. Maybe something is converting it to UTC, and that causes the mismatch. Show quote "Jim Brown" <j*@applicationsplus.com.(donotspam)> wrote in message news:E8AB3280-E2A2-4C4D-AD8D-6E9C8D900F07@microsoft.com... > I'm trying to design a front end program in VB.NET for a MS Access > database. > I'm getting Concurrency Violation errors when updating if there is a > DateTime > field in my table that has been edited in Access. Seems to be when there > is a > Time value in the column. > > This is even happening from forms generated by the Data Form Wizard, so I > don't think its code I'm writing. > > What am I missing here? > I'm getting the same problem with a form auto generated by the Data
Form Wizard (VB.NET version 2002). In my own code I'm just calling the DataAdapter.Update(dataset) method. So I think that comments I've seen elsewhere in this thread about the precision difference between Access and VB.NET's handling of time values is the answer. Here is the update logic in my own form. Private Sub DataUpdate() Dim intUpdates As Integer Me.BindingContext(Me.DsIssueLog1,"tblIssueLog").EndCurrentEdit() If Me.DsIssueLog1.HasChanges = False Then Exit Sub Try intUpdates = Me.OleDbDataAdapter1.Update(Me.DsIssueLog1) Catch ex As Exception MsgBox("Error during data update: " & ex.Message) End Try '--MsgBox(intUpdates & " updates made") End Sub On Wed, 21 Jun 2006 14:55:28 -0400, "Marina Levit [MVP]" <someone@nospam.com> wrote: Show quote >I am wondering if this can be related to conversion to/from UTC time >somehow. Maybe something is converting it to UTC, and that causes the >mismatch. > >"Jim Brown" <j*@applicationsplus.com.(donotspam)> wrote in message >news:E8AB3280-E2A2-4C4D-AD8D-6E9C8D900F07@microsoft.com... >> I'm trying to design a front end program in VB.NET for a MS Access >> database. >> I'm getting Concurrency Violation errors when updating if there is a >> DateTime >> field in my table that has been edited in Access. Seems to be when there >> is a >> Time value in the column. >> >> This is even happening from forms generated by the Data Form Wizard, so I >> don't think its code I'm writing. >> >> What am I missing here? >> >  |
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