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Thread View: borland.public.cppbuilder.database.ado
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6 total messages Started by Bas Groeneveld Wed, 04 May 2005 07:34
Use of ADO Recordset
#803
Author: Bas Groeneveld
Date: Wed, 04 May 2005 07:34
27 lines
1710 bytes 
Hi

I am having trouble using a pointer to an ADO Recordset15 object returned
from a COM control.

I can access the RecordCount variable with no problems, however I cannot
work out how to get to the actual field values.

Ideally I would like to assign the Recordset to a standard ADODataSet object
and take it from there. Is there a way to do this?

Otherwise what is the syntax to access the Recordset's field collection and
get to the field values. I was able to do this in C#.NET using:
    rs.Fields["FieldName"].Value.ToString();

I suspect that it is pretty straight forward. Is there a good reference to
this somewhere - the MSDN CD doesn't seem to help much.

Thanks
Bas
-- 

==========================================
Bas Groeneveld
Benchmark Design System and Software Engineering
PO Box 165N, Ballarat North, VIC 3350
Phone: +61 3 5333 5441  Mob: 0409 954 501
Re: Use of ADO Recordset
#804
Author: Viatcheslav V. Vassiliev
Date: Wed, 04 May 2005 10:04
46 lines
2565 bytes 
Use recordset Fields collection, it has operator [] or GetItem() method. 
ADODataSet has property Recordset that you can use, it takes 
System::DelphiInterface< _Recordset >.

//------------------------------------------
Regards,
Vassiliev V. V.
http://www.managed-vcl.com - using .Net objects in Delphi for Win32 + 
ADO.Net
http://www.oledbdirect.com - The fastest way to access MS SQL Server,
MS Jet (Access) and Interbase (through OLEDB)

"Bas Groeneveld" <nospam@nospam.com.au> �������/�������� � �������� 
���������: news:42787b1f$1@newsgroups.borland.com...
> Hi
>
> I am having trouble using a pointer to an ADO Recordset15 object returned
> from a COM control.
>
> I can access the RecordCount variable with no problems, however I cannot
> work out how to get to the actual field values.
>
> Ideally I would like to assign the Recordset to a standard ADODataSet 
> object
> and take it from there. Is there a way to do this?
>
> Otherwise what is the syntax to access the Recordset's field collection 
> and
> get to the field values. I was able to do this in C#.NET using:
>    rs.Fields["FieldName"].Value.ToString();
>
> I suspect that it is pretty straight forward. Is there a good reference to
> this somewhere - the MSDN CD doesn't seem to help much.
>
> Thanks
> Bas
> -- 
>
> ==========================================
> Bas Groeneveld
> Benchmark Design System and Software Engineering
> PO Box 165N, Ballarat North, VIC 3350
> Phone: +61 3 5333 5441  Mob: 0409 954 501
>
>
>
Re: Use of ADO Recordset
#805
Author: Bas Groeneveld
Date: Thu, 05 May 2005 00:11
44 lines
2224 bytes 
"Viatcheslav V. Vassiliev" <support@oledbdirect.com> wrote in message
news:42789e2f$1@newsgroups.borland.com...
> Use recordset Fields collection, it has operator [] or GetItem() method.

I did manage to get it going using the following

            wstUser =
adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;

However I was unable to get the [] operator working. Also the get_Item works
only on the field position, not the name. I expected to be able to go
something like

            wstUser = adoRS->Fields["User"]->Value().bstrVal;

Am I missing something here?

Also I could not access a GetItem method (as suggested in some ADO Recordset
documentation) but had to use get_Item instead.

> ADODataSet has property Recordset that you can use, it takes
> System::DelphiInterface< _Recordset >.

Thanks, I've got that to work.

Could you please tell me if the following code is correct. I especially
wondered if I need to dispose of the Recordset originally created with the
TADODataSet - or does that not exist until the Dataset is actually
populated?

    (Adodb_tlb::Recordset15*)ado = RxWClient->GetEmailAddresses(&ClientID);

    TADODataSet* ds = new TADODataSet(this);

    ds->Recordset = (Adoint::Recordset*)ado;

    ShowMessage(ds->FieldByName("Phone Number")->AsString);

    delete ds;

    ado->Close();

Cheers
Bas
Re: Use of ADO Recordset
#806
Author: Viatcheslav V. Vassiliev
Date: Thu, 05 May 2005 06:08
75 lines
3485 bytes 
In type library Item is property, and GetItem, get_Item and/or [] depends on 
program that imports type library. [] are imported, if I am not wrong, by 
C++ Builder 6, but not earlier.

>            wstUser =
> adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;

try

adoRS->Fields->getItem(WideString("User"))->get_Value();

Recordset is disposed when you assign new recordset, you do not need to 
dispose it. You need to release your pointer to recordset (ado) - you may do 
it just after assigning recordset to TADODataSet, Close() will be called by 
TADODataSet.

//------------------------------------------
Regards,
Vassiliev V. V.
http://www.managed-vcl.com - using .Net objects in Delphi for Win32 + 
ADO.Net
http://www.oledbdirect.com - The fastest way to access MS SQL Server,
MS Jet (Access) and Interbase (through OLEDB)


"Bas Groeneveld" <nospam@nospam.com.au> �������/�������� � �������� 
���������: news:42796494@newsgroups.borland.com...
> "Viatcheslav V. Vassiliev" <support@oledbdirect.com> wrote in message
> news:42789e2f$1@newsgroups.borland.com...
>> Use recordset Fields collection, it has operator [] or GetItem() method.
>
> I did manage to get it going using the following
>
>            wstUser =
> adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;
>
> However I was unable to get the [] operator working. Also the get_Item 
> works
> only on the field position, not the name. I expected to be able to go
> something like
>
>            wstUser = adoRS->Fields["User"]->Value().bstrVal;
>
> Am I missing something here?
>
> Also I could not access a GetItem method (as suggested in some ADO 
> Recordset
> documentation) but had to use get_Item instead.
>
>> ADODataSet has property Recordset that you can use, it takes
>> System::DelphiInterface< _Recordset >.
>
> Thanks, I've got that to work.
>
> Could you please tell me if the following code is correct. I especially
> wondered if I need to dispose of the Recordset originally created with the
> TADODataSet - or does that not exist until the Dataset is actually
> populated?
>
>    (Adodb_tlb::Recordset15*)ado = RxWClient->GetEmailAddresses(&ClientID);
>
>    TADODataSet* ds = new TADODataSet(this);
>
>    ds->Recordset = (Adoint::Recordset*)ado;
>
>    ShowMessage(ds->FieldByName("Phone Number")->AsString);
>
>    delete ds;
>
>    ado->Close();
>
> Cheers
> Bas
>
>
Re: Use of ADO Recordset
#807
Author: Bas Groeneveld
Date: Fri, 06 May 2005 06:48
28 lines
1924 bytes 
> In type library Item is property, and GetItem, get_Item and/or [] depends
on
> program that imports type library. [] are imported, if I am not wrong, by
> C++ Builder 6, but not earlier.

Interesting I am using C++Builder 6 but definitely don't appear to have []
available.

>
> >            wstUser =
> > adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;
>
> try
>
> adoRS->Fields->getItem(WideString("User"))->get_Value();

wstUser = adoRS->Fields->get_Item(WideString("User"))->get_Value().bstrVal;
- generates a compiler error [C++ Error] fRxWorks.cpp(134): E2285 Could not
find a match for 'Fields15::get_Item(WideString)'

wstUser = adoRS->Fields->get_Item(Variant("User"))->get_Value().bstrVal;
- compiles but generates a runtime error reported by OLECHECK

wstUser = adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;
- compiles and runs ok

Cheers
Bas
Re: Use of ADO Recordset
#809
Author: Viatcheslav V. Vassiliev
Date: Sun, 08 May 2005 17:00
63 lines
2999 bytes 
OleVariant v =
ADODataSet1->Recordset->Fields->Item[WideString("au_id")]->Value;


Remove OLECHECK (compile-time) in C++ Builder 6 (not needed in earlier):

#include <comobj.hpp>

namespace System
{
 void __fastcall CheckSafecallResult(HRESULT hr)
 {
  OleCheck(hr);
 }
}

When converting OleVariant, use (WideString)v or similar, you may have
OleVariant with other type that VT_BSTR and use .bstr() may have
unpredictable results - for example, you may get OleVariant with type
VT_NULL.

//------------------------------------------
Regards,
Vassiliev V. V.
http://www.managed-vcl.com - using .Net objects in Delphi for Win32 +
ADO.Net
http://www.oledbdirect.com - The fastest way to access MS SQL Server,
MS Jet (Access) and Interbase (through OLEDB)

"Bas Groeneveld" <nospam@nospam.com.au> �������/�������� � �������� 
���������: news:427b1331@newsgroups.borland.com...
>> In type library Item is property, and GetItem, get_Item and/or [] depends
> on
>> program that imports type library. [] are imported, if I am not wrong, by
>> C++ Builder 6, but not earlier.
>
> Interesting I am using C++Builder 6 but definitely don't appear to have []
> available.
>
>>
>> >            wstUser =
>> > adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;
>>
>> try
>>
>> adoRS->Fields->getItem(WideString("User"))->get_Value();
>
> wstUser = 
> adoRS->Fields->get_Item(WideString("User"))->get_Value().bstrVal;
> - generates a compiler error [C++ Error] fRxWorks.cpp(134): E2285 Could 
> not
> find a match for 'Fields15::get_Item(WideString)'
>
> wstUser = adoRS->Fields->get_Item(Variant("User"))->get_Value().bstrVal;
> - compiles but generates a runtime error reported by OLECHECK
>
> wstUser = adoRS->Fields->get_Item(Variant(1))->get_Value().bstrVal;
> - compiles and runs ok
>
> Cheers
> Bas
>
>
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