DBLIB.CPP
/*MS DTC Sample
**
**This example uses MS DTC (distributed transaction
**coordinator) to perform simultaneous updates on two
**SQL servers. The transaction in this example is
**client initiated. The client also initiates the
**commit operation.
**
** This sample uses the DBLib interface to communicate
** with both MS DTC and SQL server.
**
**In this particular example, the pre-installed SQL server
**table "Authors" is used.
**
** Build Instructions:
** This sample must link with the following files: ntwdblib.lib, xolehlp.lib
**
** Usage Instructions:
** Please run this program with the '-h' flag.
**
*/
//------------------------------------------------------------------------------
// Include standard header files
//------------------------------------------------------------------------------
#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <ctype.h>
//------------------------------------------------------------------------------
// Include MS DTC specific header files.
//------------------------------------------------------------------------------
#define INITGUID
#include "txdtc.h"
#include "xolehlp.h"
//------------------------------------------------------------------------------
// Include DBLib specific header files
//------------------------------------------------------------------------------
#ifndef DBNTWIN32
#define DBNTWIN32
#include <SQL.h>
#include <SQLEXT.h>
#include <sqlfront.h>
#include <sqldb.h>
#endif /* DBNTWIN32 */
//------------------------------------------------------------------------------
// Define constants
//------------------------------------------------------------------------------
#define STR_LEN40
#define TABLE_NAME"Authors"
//------------------------------------------------------------------------------
// Define datatypes
//------------------------------------------------------------------------------
typedef struct DBCONN
{
TCHARpszSrv[STR_LEN];// data source name, configured through control panel
TCHARpszUser [STR_LEN];// Login user name
TCHARpszPasswd[STR_LEN];// Login user password
TCHARpszTableName[STR_LEN];// not used - should remove.
}DBCONN;
//------------------------------------------------------------------------------
// Define Globals
//------------------------------------------------------------------------------
static DBCONNgSrv1, gSrv2;// global DB connection struct for server 1 and 2
static TCHAR gAuthorID[STR_LEN];// use 11 chars only - per Authors table.
static TCHAR gNewAddress[STR_LEN+1];// max. address length in the Author's table.
//-------------------------------------------------------------------------------
// DBLib specific global vars...
//-------------------------------------------------------------------------------
DBPROCESS*dbproc_server1;
DBPROCESS*dbproc_server2;
LOGINREC*login;
//-------------------------------------------------------------------------------
// Forward declaration of routines used.
//-------------------------------------------------------------------------------
void InitGlobals(int argc, char **argv);
void LogonToDB(DBPROCESS **dbp, DBCONN *ptr);
void Enlist(DBCONN *ptr,DBPROCESS *dbp, ITransaction *pTransaction);
void ExecuteStatement(DBCONN *ptr, DBPROCESS *dbp, LPTSTR pszBuf);
//-------------------------------------------------------------------------------
// DBLib error and message handlers
//-------------------------------------------------------------------------------
int err_handler(DBPROCESS*, int, int, int, char*, char*);
int msg_handler(DBPROCESS*, DBINT, int, int, char*);
//-------------------------------------------------------------------------------
// main()
//-------------------------------------------------------------------------------
void main(int argc, char **argv)
{
ITransactionDispenser*pTransactionDispenser;
ITransaction*pTransaction;
HRESULThr = S_OK ;
TCHARSqlStatement[STR_LEN*2];
// Initialize globals & validate command line arguments
InitGlobals(argc,argv);
// set error/msg handlers for this program
dbmsghandle((DBMSGHANDLE_PROC)msg_handler);
dberrhandle((DBERRHANDLE_PROC)err_handler);
// initialize LOGINREC structure
login = dblogin();
// Obtain the ITransactionDispenser Interface pointer
// by calling DtcGetTransactionManager()
hr = DtcGetTransactionManager( NULL, // LPTSTRpszHost,
NULL, // LPTSTRpszTmName,
IID_ITransactionDispenser,// /* in */ REFIIDrid,
0,// /* in */ DWORDdwReserved1,
0, // /* in */ WORDwcbReserved2,
0,// /* in */ voidFAR * pvReserved2,
(void **)&pTransactionDispenser // /*out */ void**ppvObject
) ;
if (FAILED (hr))
{
printf("DtcGetTransactionManager failed: %x\n", hr);
exit (1);
}
// Establish connection to database on server#1
LogonToDB(&dbproc_server1,&gSrv1);
// Establish connection to database on server#2
LogonToDB(&dbproc_server2,&gSrv2);
// Loop performing distributed transactions
for (INT i = 0; i < 5; i++)
{
// Initiate an MS DTC transaction
hr = pTransactionDispenser->BeginTransaction(
NULL,///* [in] */ IUnknown __RPC_FAR *punkOuter,
ISOLATIONLEVEL_ISOLATED,///* [in] */ ISOLEVEL isoLevel,
ISOFLAG_RETAIN_DONTCARE,// /* [in] */ ULONG isoFlags,
NULL,///* [in] */ITransactionOptions *pOptions
&pTransaction///* [out] */ ITransaction **ppTransaction
) ;
if (FAILED (hr))
{
printf("BeginTransaction failed: %x\n",hr);
exit(1);
}
// Enlist each of the data sources on the transaction
Enlist(&gSrv1,dbproc_server1,pTransaction);
Enlist(&gSrv2,dbproc_server2,pTransaction);
// Generate the SQL statement to execute on each of the databases
sprintf(SqlStatement,
"update authors set address = '%s_%d' where au_id = '%s'",
gNewAddress,i,gAuthorID);
// Perform updates on both of the DBs participating in the transaction
ExecuteStatement(&gSrv1,dbproc_server1,SqlStatement);
ExecuteStatement(&gSrv2,dbproc_server2,SqlStatement);
// Commit the transaction
hr = pTransaction->Commit(0,0,0);
if (FAILED(hr))
{
printf("pTransaction->Commit() failed: %x\n",hr);
exit(1);
}
// At end of each transaction, pTransaction-Release() must be called.
hr = pTransaction->Release();
if (FAILED(hr))
{
printf("pTransaction->Release() failed: %x\n",hr);
exit(1);
}
printf("Successfully committed Transaction #%d\n",i);
} // for
// release the transaction dispenser
pTransactionDispenser->Release();
// release DBLib resources and exit
dbexit();
}
//-------------------------------------------------------------------------------
void InitGlobals(INT argc, char **argv)
{
TCHAR Usage[] = "\n [-S1 server_1] \n"\
" [-U1 user_name_1]\n"\
" [-P1 passwd_1]\n"\
" [-S2 server_2]\n"\
" [-U2 user_name_2]\n"\
" [-P2 passwd_2]\n"\
" [-ID au_id]\n"\
" [-Ad new_address\n"\
" [-h Usage]\n";
// Init Table name
lstrcpy(gSrv1.pszTableName,TABLE_NAME);
lstrcpy(gSrv2.pszTableName,TABLE_NAME);
// Null login info, set defaults as appropriate
lstrcpy(gSrv1.pszSrv,"");
lstrcpy(gSrv1.pszUser,"sa");
lstrcpy(gSrv1.pszPasswd,"");
lstrcpy(gSrv2.pszSrv,"");
lstrcpy(gSrv2.pszUser,"sa");
lstrcpy(gSrv2.pszPasswd,"");
lstrcpy(gAuthorID,"172-32-1176");// default au_id value from authors table in pubs db.
// scan command line arguments for user input.
for (INT i = 1; i < argc; i++)
{
if (*argv[i] == '-' || *argv[i] == '/')
{
switch (argv[i][1])
{
// get the server or DSN name
case 's':
case 'S':
switch (argv[i][2])
{
case '1':
lstrcpy(gSrv1.pszSrv,argv[++i]);
break;
case '2':
lstrcpy(gSrv2.pszSrv,argv[++i]);
break;
default:
printf("Invalid Input %s\n",argv[i]);
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
};
break;
// get user name
case 'u':
case 'U':
switch (argv[i][2])
{
case '1':
lstrcpy(gSrv1.pszUser,argv[++i]);
break;
case '2':
lstrcpy(gSrv2.pszUser,argv[++i]);
break;
default:
printf("Invalid Input %s\n",argv[i]);
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
};
break;
// get password
case 'p':
case 'P':
switch (argv[i][2])
{
case '1':
lstrcpy(gSrv1.pszPasswd,argv[++i]);
break;
case '2':
lstrcpy(gSrv2.pszPasswd,argv[++i]);
break;
default:
printf("Invalid Input %s\n",argv[i]);
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
};
break;
// get au_id, overriding default value.
case 'i':
case 'I':
lstrcpy(gAuthorID,argv[++i]);
break;
// get new address to associate with the au_id
case 'a':
case 'A':
lstrcpy(gNewAddress,argv[++i]);
break;
case '?':
case 'h':
case 'H':
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
break;
default:
printf("Invalid Input: %s\n",argv[i]);
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
}
}
else
{
printf("Illegal command line argument #%d, %s\n",i,argv[i]);
printf("\nUsage: %s %s",argv[0],Usage);
exit(1);
}
}
printf("-----------------------------\n");
printf("MS DTC/DBLib Sample Configuration parameters\n");
printf( "server_1: %s\n"\
"user_name_1: %s\n"\
"passwd_1: %s\n"\
"server_2: %s\n"\
"user_name_2: %s\n"\
"passwd_2: %s\n",
gSrv1.pszSrv,gSrv1.pszUser,gSrv1.pszPasswd,
gSrv2.pszSrv,gSrv2.pszUser,gSrv2.pszPasswd);
printf("-----------------------------\n");
}
//-------------------------------------------------------------------------------
void LogonToDB(DBPROCESS **dbp, DBCONN *ptr)
{
DBSETLUSER(login, ptr->pszUser);
DBSETLPWD(login, ptr->pszPasswd);
DBSETLAPP(login, "example");
*dbp = dbopen (login, ptr->pszSrv);
if (*dbp == NULL)
{
printf ("\nLogin to server: %s failed, exiting!\n",ptr->pszSrv);
exit (ERREXIT);
}
/* Use the "pubs" database. */
dbuse(*dbp, "pubs");
}
//-------------------------------------------------------------------------------
void Enlist(DBCONN *ptr, DBPROCESS *dbp, ITransaction *pTransaction)
{
RETCODE rc = 0;
rc = dbenlisttrans (dbp, pTransaction);
if (FAIL == rc)
{
printf("\ndbenlisttrans() failed: %x\n",rc);
exit(1);
}
}
// ---------------------------------------------------------------------------
void ExecuteStatement(DBCONN *ptr, DBPROCESS *dbp, char *pszBuf)
{
RETCODE rc = 0;
dbcmd(dbp,pszBuf);
rc = dbsqlexec(dbp);
if (FAIL == rc)
{
// one or both of the servers failed to prepare
printf("dbsqlexec() failed\n");
exit(1);
}
rc = dbresults(dbp);
if (rc != SUCCEED)
{
printf("dbresults() failed: %x\n",rc);
exit(1);
}
}
// ---------------------------------------------------------------------------
/* Message and error handling functions. */
int msg_handler(DBPROCESS *dbproc, DBINT msgno, int msgstate, int severity, char *msgtext)
{
/*Msg 5701 is just a USE DATABASE message, so skip it.*/
if (msgno == 5701)
return (0);
/*Print any severity 0 message as is, without extra stuff.*/
if (severity == 0)
{
printf ("%s\n",msgtext);
return (0);
}
printf("SQL Server message %ld, severity %d:\n\t%s\n",
msgno, severity, msgtext);
if (severity >>= 16)
{
printf("Program Terminated! Fatal SQL Server error.\n");
exit(ERREXIT);
}
return (0);
}
// ---------------------------------------------------------------------------
int err_handler(DBPROCESS *dbproc, int severity, int dberr, int oserr, char *dberrstr, char *oserrstr)
{
if ((dbproc == NULL) || (DBDEAD(dbproc)))
return (INT_EXIT);
else
{
printf ("DB-LIBRARY error: \n\t%s\n", dberrstr);
if (oserr != DBNOERR)
printf ("Operating system error:\n\t%s\n", oserrstr);
}
return (INT_CANCEL);
}
// ---------------------------------------------------------------------------