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"ht" <ht_ftp@km169.net> д���ʼ� news:4549a412@newsgroups.borland.com...
I used ADO to access a Ms Access database.I put a TAdoConnection, a
TADOTable, a TDataSource and a TDBGrid into the Form,the I have actived the
dataset,but some datas displayed in the grid is dislike that in the Ms
Access.especially the  field whose type is DateTime,for example:In ms access
a record's datetime field is 2006-11-20 12:12:31,but in my test application,
this field has changed to  2006-11-20 12:12:30,so I tested this database in
vb by ocx,the result is correct.Is the reason in my access table???

> 2006-11-20 12:12:31
> 2006-11-20 12:12:31

I see no difference in these two date values.  What did you mean to type?

To control the display format of a field you can find the field in the 
dataset and then modify the 'DisplayFormat' property to your liking.

For instance to specify that the display format should be "2006/11/20":

  TDateTimeField* field = dynamic_cast <TDateTimeField*>
    (DataSet1->Fields->FieldByName("SomeDateField"));
  if (field)
    field->DisplayFormat = "yyyy/mm/dd";

HTH,
- Clayton 

When I first read your second message it appeared to me that you 
accidentally replied to your own message.  However, I just read it again and 
saw that you changed a 31 to a 30.  For future reference, when you are 
correcting something you wrote please make it obvious.  For instance:

  I mistyped the bad date.  It should have been "2006-11-20 12:12:30".

This would make it apparent why the second post exists.

However, to answer your question.  It could be a floating point rounding 
error though I've never seen that happen to a TDateTime before without some 
sort of arithmetic involved.

I'll keep my eyes open to try to find out what the issue is.  Hopefully 
someone else that knows what's going on will respond.

- Clayton 

"Clayton Arends" <nospam_claytonarends@hotmail.com> д����Ϣ����:454a2986$1@newsgroups.borland.com...
> When I first read your second message it appeared to me that you 
> accidentally replied to your own message.  However, I just read it again 
> and saw that you changed a 31 to a 30.  For future reference, when you are 
> correcting something you wrote please make it obvious.  For instance:
>
>  I mistyped the bad date.  It should have been "2006-11-20 12:12:30".
>
> This would make it apparent why the second post exists.
>
> However, to answer your question.  It could be a floating point rounding 
> error though I've never seen that happen to a TDateTime before without 
> some sort of arithmetic involved.
>
> I'll keep my eyes open to try to find out what the issue is.  Hopefully 
> someone else that knows what's going on will respond.
>
> - Clayton
>
Thank you,Clayton!I have seen my program again,I thought maybe you are 
right.Because the DateTime was reprented as a float value in the access,and 
In my application I put data into the table every 200ms, perhaps the 
difference was the different convertion method between Borland and 
Microsoft.so you are right:It could be a floating point rounding . 

I experienced something similar to this one, when I was migrating
DateTime values from an MS Access db to MySQL using TADOQuery. My code
looked something like this:

while (!adoAccess->Eof)
{
  adoMySQL->Append();
  adoMySQLDT->Value = adoAccessDT->Value;
  adoMySQL->Post();

  adoAccess->Next();
}

When I inspected the migrated records on MySQL, I found out that most
of the records were off by a second. But if I do this:

adoMySQLDT->Value = StrToDateTime(DateTimeToStr(adoAccessDT->Value));

The resulting records are correct.

Another baffling thing is prior to this one, I had no problem migrating
DateTime values from Interbase/Firebird (using DBX) to MySQL (using
ADO).

- Erol