在VC程序中ADO连接 SQL SERVER数据库如何进行事务处理
在VC程序中ADO连接 SQL SERVER数据库如何进行事务处理
ADO连接也可以像ODBC连接一样使用BeginTran /rollback/Commit tran.不用存储过程.
问题点数：100、回复次数：7Top
1 楼leecyi（leecyi）回复于 2002-05-14 11:53:25 得分 0
UTop
2 楼dyw（旺仔）回复于 2002-05-14 12:07:53 得分 0
//Section 1
// BeginBeginTransCpp
#import "C:\Program Files\Common Files\System\ADO\msado15.dll" \
no_namespace rename("EOF", "EndOfFile")
#include <stdio.h>
#include <ole2.h>
#include <conio.h>
#include <assert.h>
#include <malloc.h>
#include "BeginTransX.h"
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void BeginTransX(void);
void PrintProviderError(_ConnectionPtr pConnection);
void main()
{
if(FAILED(::CoInitialize(NULL)))
return;
BeginTransX();
//Wait here for user to see the output.
printf("\nPress any key to continue...");
getch();
::CoUninitialize();
}
///////////////////////////////////////////////////////////
// //
// BeginTransX Function //
// //
///////////////////////////////////////////////////////////
void BeginTransX()
{
// Define ADO object pointers.
// Initialize pointers on define.
// These are in the ADODB:: namespace.
_RecordsetPtr rstTitles = NULL;
_ConnectionPtr pConnection = NULL;
//Define Other Variables
HRESULT hr = S_OK;
IADORecordBinding *picRs = NULL; //Interface Pointer declared...
CTitlesRs titlrs;
_bstr_t strTitle;
_bstr_t strMessage;
LPSTR p_TempStr = NULL;
char chKey;
int i = 0;
try
{
// open connection.
_bstr_t strCnn("Provider=sqloledb;Data Source=MyServer;"
"Initial Catalog=pubs;User Id=sa;Password=;");
TESTHR(pConnection.CreateInstance(__uuidof(Connection)));
TESTHR(pConnection->Open(strCnn,"","",adConnectUnspecified));
rstTitles.CreateInstance(__uuidof(Recordset));
rstTitles->CursorType = adOpenDynamic;
rstTitles->LockType = adLockPessimistic;
// open Titles table
TESTHR(rstTitles->Open("titles",
_variant_t((IDispatch*)pConnection,true),
adOpenDynamic, adLockPessimistic,adCmdTable));
rstTitles->MoveFirst();
pConnection->BeginTrans();
//Open an IADORecordBinding interface pointer which
//we'll use for Binding Recordset to a class
TESTHR(rstTitles->QueryInterface(
__uuidof(IADORecordBinding), (LPVOID*)&picRs));
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3 楼dyw（旺仔）回复于 2002-05-14 12:08:28 得分 98
//Section 2
//Bind the Recordset to a C++ Class here
TESTHR(picRs->BindToRecordset(&titlrs));
// Loop through recordset and ask user if he wants
// to change the type for a specified title.
// Allocate memory to p_TempStr string pointer.
p_TempStr = (LPSTR) malloc(sizeof(titlrs.m_szT_type));
// Check for null string.
assert(p_TempStr != NULL);
while (VARIANT_FALSE == rstTitles->EndOfFile)
{
// Remove blank string
strcpy(p_TempStr,strtok(titlrs.m_szT_type," "));
// Compare type with psychology
if (!strcmp(p_TempStr,"psychology"))
{
strTitle = titlrs.m_szT_title;
strMessage = "Title: " + strTitle +
"\n Change type to Self help?(y/n)";
// Change the title for specified employee
printf("%s\n",(LPCSTR)strMessage);
do
{
chKey = getch();
}while(chKey != 'y' && chKey !='n');
if(chKey == 'y')
{
// Copy "self_help" title field
strcpy(titlrs.m_szT_type,"self_help");
picRs->Update(&titlrs);
}
}
rstTitles->MoveNext();
}
// Ask if the User wants to commit to all the
//Changes made above
printf("\n\n Save all changes(y/n)?");
do
{
chKey = getch();
}while(chKey != 'y' && chKey !='n');
if(chKey == 'y')
// Save the changes to the title table
pConnection->CommitTrans();
else
// Unsave the changes to the title table
pConnection->RollbackTrans();
// Print current data in recordset.
rstTitles->Requery(0);
// Move to the first record of the title table
rstTitles->MoveFirst();
printf("\n\nPress any key to continue...");
getch();
// Clear the screen for the next display
system("cls");
// Open IADORecordBinding interface pointer again
// for binding Recordset to a class.
TESTHR(rstTitles->QueryInterface(
__uuidof(IADORecordBinding),
(LPVOID*)&picRs));
// Rebind the Recordset to a C++ Class.
TESTHR(picRs->BindToRecordset(&titlrs));
while (!rstTitles->EndOfFile)
{
i= i+1;
if (i % 23 == 0)
{
printf("\nPress any key to continue...");
getch();
//Clear the screen for the next display
system("cls");
}
printf("%s - %s\n",titlrs.m_szT_title,titlrs.m_szT_type);
rstTitles->MoveNext();
}
// Restore original data becasue this is a demonstration.
rstTitles->MoveFirst();
while (VARIANT_FALSE == rstTitles->EndOfFile)
{
strcpy(p_TempStr,titlrs.m_szT_type);
p_TempStr = strtok(p_TempStr," ");
if (!strcmp(p_TempStr,"self_help"))
{
strcpy(titlrs.m_szT_type,"psychology");
picRs->Update(&titlrs);
}
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4 楼leecyi（leecyi）回复于 2002-05-14 12:08:43 得分 0
UPTop
5 楼dyw（旺仔）回复于 2002-05-14 12:09:06 得分 0
//Section 3
rstTitles->MoveNext();
}
// Deallocate the memory
free(p_TempStr);
// Clean up objects before exit.
rstTitles->Close();
pConnection->Close();
//Release IADORecordset Interface
if (picRs)
picRs->Release();
}
catch(_com_error &e)
{
// Notify the user of errors if any.
_bstr_t bstrSource(e.Source());
_bstr_t bstrDescription(e.Description());
PrintProviderError(pConnection);
printf("Source : %s\n",(LPCSTR)bstrSource);
printf("Description : %s\n",(LPCSTR)bstrDescription);
}
};
///////////////////////////////////////////////////////////
// //
// PrintProviderError Function //
// //
///////////////////////////////////////////////////////////
void PrintProviderError(_ConnectionPtr pConnection)
{
// Print Provider Errors from Connection object.
// pErr is a record object in the Connection's Error collection.
ErrorPtr pErr = NULL;
long nCount = 0;
long i = 0;
if( (pConnection->Errors->Count) > 0)
{
nCount = pConnection->Errors->Count;
// Collection ranges from 0 to nCount -1.
for(i = 0; i < nCount; i++)
{
pErr = pConnection->Errors->GetItem(i);
printf("Error number: %x\t%s\n", pErr->Number,(LPCSTR) pErr->Description);
}
}
}
// EndBeginTransCpp
BeginTransX.h:
// BeginBeginTransH
#include "icrsint.h"
//This Class extracts only title and type
class CTitlesRs : public CADORecordBinding
{
BEGIN_ADO_BINDING(CTitlesRs)
//Column title is the 2nd field in the recordset
ADO_VARIABLE_LENGTH_ENTRY2(2, adVarChar, m_szT_title,
sizeof(m_szT_title), lT_titleStatus, FALSE)
//Column type is the 3rd field in the recordset
ADO_VARIABLE_LENGTH_ENTRY2(3, adVarChar, m_szT_type,
sizeof(m_szT_type), lT_typeStatus, TRUE)
END_ADO_BINDING()
public:
CHAR m_szT_title[150];
ULONG lT_titleStatus;
CHAR m_szT_type[40];
ULONG lT_typeStatus;
};
// EndBeginTransH
// -- end --Top
6 楼liuty2006（）回复于 2002-05-14 12:16:28 得分 2
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7 楼lenity（慈悲无敌）回复于 2002-06-19 12:10:08 得分 0
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