Utilizzare le caratteristiche avanzate di data e ora (OLE DB)

Articolo
05/07/2013
In questo viene illustrato come utilizzare le caratteristiche di data e ora introdotte in SQL Server 2008. Nell'esempio vengono utilizzati i quattro nuovi tipi di dati relativi a data e ora, ovvero date, time, datetime2 e datetimeoffset, per eseguire comandi con parametri e recuperare risultati di set di righe.
Per l'esempio è necessario il database di esempio AdventureWorks, che è possibile scaricare dalla home page del sito relativo a progetti della community ed esempi per Microsoft SQL Server.
Nota sulla sicurezza
Se possibile, utilizzare l'autenticazione di Windows. Se l'autenticazione di Windows non è disponibile, agli utenti verrà richiesto di immettere le credenziali in fase di esecuzione. Evitare di archiviare le credenziali in un file. Se è necessario rendere persistenti le credenziali, è consigliabile crittografarle utilizzando l'API di crittografia Win32.
Esempio

Il primo listato di codice (Transact-SQL) consente di creare una stored procedure utilizzata dall'esempio.
Compilare il secondo listato di codice (C++) con ole32.lib oleaut32.lib ed eseguirlo. In questa applicazione viene eseguita la connessione all'istanza predefinita di SQL Server nel computer in uso. In alcuni sistemi operativi Windows sarà necessario modificare (local) o (localhost) impostando il valore sul nome dell'istanza di SQL Server. Per connettersi a un'istanza denominata, modificare la stringa di connessione da L"(local)" in L"(local)\\nome", dove nome rappresenta l'istanza denominata. Per impostazione predefinita, SQL Server Express viene installato in un'istanza denominata. Verificare che nella variabile di ambiente INCLUDE sia presente la directory che contiene sqlncli.h.
Il terzo listato di codice (Transact-SQL) consente di eliminare una stored procedure utilizzata dall'esempio.
CREATE PROCEDURE sp_datetimetypes
   @date_param DATE OUTPUT, 
   @time_param TIME(7) OUTPUT,
   @datetime2_param DATETIME2(7) OUTPUT,
   @datetimeoffset_param DATETIMEOFFSET(7) OUTPUT
AS 
SELECT @date_param, @time_param, @datetime2_param, @datetimeoffset_param
GO

// compile with: ole32.lib oleaut32.lib
#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <tchar.h>
#include <sqlncli.h>
#include "oledberr.h"
#include <stddef.h>

static const DBLENGTH sc_cchStrLen = 64;

struct DateTimeTypeEx {
   DBSTATUS status;
   DBLENGTH length;
   union {
      DBTIMESTAMP ts;
      DBDATE d;
      DBTIME2 t;
      DBTIMESTAMPOFFSET tso;
      WCHAR wstr[sc_cchStrLen];
      CHAR str[sc_cchStrLen];
   };
};

struct TypePrecScalEx {
   DBTYPE wType;
   BYTE bPrec;
   BYTE bScale;
   WCHAR wszTypeName[64];
   DBLENGTH ulSize;
};

HRESULT InitializeAndEstablishConnection (IUnknown ** ppUnkDBInitialize)  {
   HRESULT hr = S_OK;
   IDBProperties * pIDBProperties = NULL;
   IDBInitialize * pIDBInitialize = NULL;
   DBPROPSET rgInitPropSet[1] = {0};
   DBPROP InitProperties[4] = {0};

   *ppUnkDBInitialize = NULL;

   // Initialize the COM library.
   CoInitialize(NULL);

   // Obtain access to the SQL Server Native Client OLE DB provider.
   hr = CoCreateInstance(CLSID_SQLNCLI11, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (void **) &pIDBInitialize);

   // Initialize property values needed to establish connection.
   for (unsigned int i = 0 ; i < 4 ; i++) 
      VariantInit(&InitProperties[i].vValue);

   // Server name.
   // See DBPROP structure for more information on InitProperties
   InitProperties[0].dwPropertyID = DBPROP_INIT_DATASOURCE;
   InitProperties[0].vValue.vt = VT_BSTR;
   InitProperties[0].vValue.bstrVal= SysAllocString(L"localhost");
   InitProperties[0].dwOptions = DBPROPOPTIONS_REQUIRED;
   InitProperties[0].colid = DB_NULLID;

   // Database.
   InitProperties[1].dwPropertyID = DBPROP_INIT_CATALOG;
   InitProperties[1].vValue.vt = VT_BSTR;
   InitProperties[1].vValue.bstrVal = SysAllocString(L"AdventureWorks");
   InitProperties[1].dwOptions = DBPROPOPTIONS_REQUIRED;
   InitProperties[1].colid = DB_NULLID;

   // Username (login).
   InitProperties[2].dwPropertyID = DBPROP_AUTH_INTEGRATED;
   InitProperties[2].vValue.vt = VT_BSTR;
   InitProperties[2].vValue.bstrVal = SysAllocString(L"SSPI");
   InitProperties[2].dwOptions = DBPROPOPTIONS_REQUIRED;
   InitProperties[2].colid = DB_NULLID;
   InitProperties[3].dwOptions = DBPROPOPTIONS_REQUIRED;
   InitProperties[3].colid = DB_NULLID;

   // Construct the DBPROPSET structure(rgInitPropSet). The DBPROPSET structure is used to pass 
   // an array of DBPROP structures (InitProperties) to the SetProperties method.
   rgInitPropSet[0].guidPropertySet = DBPROPSET_DBINIT;
   rgInitPropSet[0].cProperties = 4;
   rgInitPropSet[0].rgProperties = InitProperties;

   // Set initialization properties.
   hr = pIDBInitialize->QueryInterface(IID_IDBProperties, (void **)&pIDBProperties);
   hr = pIDBProperties->SetProperties(1, rgInitPropSet); 
   pIDBProperties->Release();

   // Establish the connection to the data source.
   hr = pIDBInitialize->Initialize();   

   if (S_OK == hr)
      *ppUnkDBInitialize = pIDBInitialize;

   return hr;
}

//   This function creates an OLE DB Session object from the given DataSource object.
HRESULT myCreateSession(IUnknown * pUnkDataSource, REFIID riid, IUnknown ** ppUnkSession) {
   HRESULT hr;
   IDBCreateSession * pIDBCreateSession = NULL;

   // Create a session object from a data source object
   hr = pUnkDataSource->QueryInterface(IID_IDBCreateSession, (void**)&pIDBCreateSession);
   hr = pIDBCreateSession->CreateSession(NULL, riid, ppUnkSession);   

   if (pIDBCreateSession)
      pIDBCreateSession->Release();

   return hr;
}

// This function takes an IUnknown pointer on a Session object and attempts to create a Command object
// object using the Session's IDBCreateCommand interface. Since this interface is optional, this may fail.
HRESULT myCreateCommand(IUnknown * pUnkSession, IUnknown ** ppUnkCommand) {
   HRESULT hr;
   IDBCreateCommand * pIDBCreateCommand = NULL;

   // Attempt to create a Command object from the Session object
   hr = pUnkSession->QueryInterface(IID_IDBCreateCommand, (void**)&pIDBCreateCommand);   
   hr = pIDBCreateCommand->CreateCommand(NULL, IID_ISSCommandWithParameters, ppUnkCommand);   

   if (pIDBCreateCommand)
      pIDBCreateCommand->Release();

   return hr;
}

// This function takes an IUnknown pointer on a Command object and creates a new Rowset object as follows:
// * Sets the given properties on the Command object. These properties will be
//   applied by the provider to any Rowset created by this Command.
// * Sets the given command text for the Command.
// * Executes the command to create a new Rowset object.
HRESULT myExecuteCommand(ISSCommandWithParameters * pUnkCommand, ULONG cPropSets, DBPROPSET* rgPropSets, IUnknown ** ppUnkRowset) {
   HRESULT hr;
   ICommandText * pICommandText = NULL;
   ICommandProperties * pICommandProperties = NULL;
   IAccessor * pIAccessor = NULL;
   IAccessor * pIAccessorRowset = NULL;
   HACCESSOR hAccessor = NULL;
   HACCESSOR hAccessorWstr = NULL;
   DBCOUNTITEM cRowsObtained = 0;
   HROW * rghRow = NULL;

   static const DBCOUNTITEM sc_cCol = 4;
   static const DB_UPARAMS sc_cParams = sc_cCol;
   static const DBROWCOUNT sc_cRows = 1;

   // Bindings and values
   DateTimeTypeEx rgDttEx[sc_cCol] = {0};
   DBBINDING rgBindings[sc_cCol] = {0};
   DBBINDSTATUS rgStatus[sc_cCol] = {0};
   DBBINDING rgBindingsWstr[sc_cCol] = {0};

   TypePrecScalEx rgTpsEx[sc_cCol] = { 
      DBTYPE_DBDATE, 0, 0, L"DATE", sizeof(DBDATE),
      DBTYPE_DBTIME2, 0, 4, L"TIME", sizeof(DBTIME2),
      DBTYPE_DBTIMESTAMP, 0, 4, L"DATETIME2", sizeof(DBTIMESTAMP),
      DBTYPE_DBTIMESTAMPOFFSET, 0, 4, L"DATETIMEOFFSET", sizeof(DBTIMESTAMPOFFSET)  
   };

   // Command, bindings, and param values
   WCHAR * pwszCommandText = L"{call sp_datetimetypes(?,?,?,?)}";
   DB_UPARAMS rgParamOrdinals[sc_cParams] = {0};
   DBPARAMBINDINFO rgParamBindInfo[sc_cParams] = {0};
   DBPARAMS myDBPARAMS = {0};

   // Set param ordinals
   for (unsigned int i = 0; i < sc_cParams; i++)
      rgParamOrdinals[i] = i + 1;

   // Set param bind info
   for (unsigned int i = 0; i < sc_cParams; i++) {
      rgParamBindInfo[i].pwszDataSourceType = rgTpsEx[i].wszTypeName;
      rgParamBindInfo[i].bPrecision = rgTpsEx[i].bPrec;
      rgParamBindInfo[i].bScale = rgTpsEx[i].bScale;
      rgParamBindInfo[i].dwFlags = DBPARAMFLAGS_ISINPUT | DBPARAMFLAGS_ISOUTPUT | DBPARAMFLAGS_ISNULLABLE;
      rgParamBindInfo[i].pwszName = NULL;
      rgParamBindInfo[i].ulParamSize = rgTpsEx[i].ulSize;
   }

   // Prepare bindings
   for (unsigned int i = 0; i < sc_cParams; i++) {
      rgBindings[i].iOrdinal = i+1;
      rgBindings[i].obValue =  (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);
      rgBindings[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindings[i].obStatus = (i * sizeof(DateTimeTypeEx));
      rgBindings[i].pTypeInfo = NULL;
      // rgBindings[i].pObject not used
      rgBindings[i].pBindExt = NULL;
      rgBindings[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindings[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindings[i].eParamIO = DBPARAMIO_INPUT | DBPARAMIO_OUTPUT;
      rgBindings[i].cbMaxLen = 0;   // ignored for fixed length types
      rgBindings[i].dwFlags = 0;
      rgBindings[i].wType = rgTpsEx[i].wType;
      rgBindings[i].bPrecision = rgTpsEx[i].bPrec;
      rgBindings[i].bScale = rgTpsEx[i].bScale;

      rgBindingsWstr[i].iOrdinal = i+1;
      rgBindingsWstr[i].obValue = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);
      rgBindingsWstr[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindingsWstr[i].obStatus = (i * sizeof(DateTimeTypeEx));
      rgBindingsWstr[i].pTypeInfo = NULL;
      // rgBindingsWstr[i].pObject not used
      rgBindingsWstr[i].pBindExt = NULL;
      rgBindingsWstr[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindingsWstr[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindingsWstr[i].eParamIO = DBPARAMIO_NOTPARAM ;
      rgBindingsWstr[i].cbMaxLen = sizeof(WCHAR)*sc_cchStrLen; 
      rgBindingsWstr[i].dwFlags = 0;
      rgBindingsWstr[i].wType = DBTYPE_WSTR;
      rgBindingsWstr[i].bPrecision = 0;
      rgBindingsWstr[i].bScale = 0;
   }

   // Create accessors
   hr = pUnkCommand->QueryInterface(IID_IAccessor, (void**)&pIAccessor);
   hr =  pIAccessor->CreateAccessor (DBACCESSOR_PARAMETERDATA, sc_cCol, rgBindings, 0, &hAccessor, rgStatus); 

   myDBPARAMS.cParamSets = 1;
   myDBPARAMS.pData = rgDttEx;
   myDBPARAMS.hAccessor = hAccessor;

   // Set the properties on the Command object
   hr = pUnkCommand->QueryInterface(IID_ICommandProperties, (void**)&pICommandProperties);   
   hr = pICommandProperties->SetProperties(cPropSets, rgPropSets);   

   // Set the text for this Command, using the default command text
   // dialect. All providers that support commands must support this
   // dialect and providers that support SQL must be able to recognize
   // an SQL command as SQL when this dialect is specified
   hr = pUnkCommand->QueryInterface(IID_ICommandText, (void**)&pICommandText);
   hr = pICommandText->SetCommandText(DBGUID_DEFAULT, pwszCommandText);

   // Set value in preparation for executing command
   rgDttEx[0].length = sizeof(DBDATE);
   rgDttEx[0].d.year = 1979;
   rgDttEx[0].d.month = 4;
   rgDttEx[0].d.day = 1;

   rgDttEx[1].length = sizeof(DBTIME2);
   rgDttEx[1].t.hour = 2;
   rgDttEx[1].t.minute = 3;
   rgDttEx[1].t.second = 5;
   rgDttEx[1].t.fraction = 800000;

   rgDttEx[2].length = sizeof(DBTIMESTAMP);
   rgDttEx[2].ts.year = 1776;
   rgDttEx[2].ts.month = 7;
   rgDttEx[2].ts.day = 4;
   rgDttEx[2].ts.hour = 21;
   rgDttEx[2].ts.minute = 39;
   rgDttEx[2].ts.second = 59;
   rgDttEx[2].ts.fraction = 5000000;

   rgDttEx[3].length = sizeof(DBTIMESTAMPOFFSET);
   rgDttEx[3].tso.year = 1979;
   rgDttEx[3].tso.month = 4;
   rgDttEx[3].tso.day = 1;
   rgDttEx[3].tso.hour = 2;
   rgDttEx[3].tso.minute = 3;
   rgDttEx[3].tso.second = 5;
   rgDttEx[3].tso.fraction = 0;
   rgDttEx[3].tso.timezone_hour = -5;
   rgDttEx[3].tso.timezone_minute = 0;

   // Add parameter info
   hr = pUnkCommand->SetParameterInfo(sc_cParams, rgParamOrdinals, rgParamBindInfo);   

   // Execute the Command. User could enter a non-row returning command, so we check for
   // that and return failure to prevent the display of the non-existant rowset by the caller
   hr = pICommandText->Execute(NULL, IID_IRowset, &myDBPARAMS, NULL, ppUnkRowset);   

   if (FAILED(hr) || !*ppUnkRowset) {
      printf("\nThe command executed, but did not " \
         "return a rowset.\nNo rowset will be displayed.\n");
      hr = E_FAIL;      
      // exit(0);
   }
   else
   {
      // Create accessor for rowset
      hr = (*ppUnkRowset)->QueryInterface(IID_IAccessor, (void**)&pIAccessorRowset);
      hr =  pIAccessorRowset->CreateAccessor (DBACCESSOR_ROWDATA, sc_cCol, rgBindingsWstr, 0, &hAccessorWstr, rgStatus); 
      hr = ((IRowset*)*ppUnkRowset)->GetNextRows(DB_NULL_HCHAPTER, 0, sc_cRows, &cRowsObtained, &rghRow);
      hr = ((IRowset*)*ppUnkRowset)->GetData(rghRow[0], hAccessorWstr, rgDttEx);   

      printf ("Data returned from sp_datetimetypes -------------\n%32ls%32ls%32ls%32ls\n", 
         rgDttEx[0].wstr, rgDttEx[1].wstr, rgDttEx[2].wstr, rgDttEx[3].wstr);
   }
   if (pICommandText)
      pICommandText->Release();

   if (pICommandProperties)
      pICommandProperties->Release();

   if (pIAccessor)
      pIAccessor->Release();

   if (pIAccessorRowset)
      pIAccessorRowset->Release();

   return hr;
}

HRESULT myTableDefinition (IUnknown * pUnkDataSource, DBID *  pTableID, IUnknown ** ppUnkRowset) {
   HRESULT hr;
   ITableDefinition * pITableDefinition = NULL;
   HACCESSOR hAccessor = NULL;

   static const DBORDINAL sc_cCol = 4;

   DBCOLUMNDESC rgColumnDescs[sc_cCol];

   pTableID->eKind = DBKIND_NAME;
   pTableID->uName.pwszName = L"datetimetypestable";

   rgColumnDescs[0].pwszTypeName = L"date";
   rgColumnDescs[0].pTypeInfo = NULL;
   rgColumnDescs[0].rgPropertySets = NULL;
   rgColumnDescs[0].pclsid = NULL;
   rgColumnDescs[0].cPropertySets = 0;
   rgColumnDescs[0].ulColumnSize = 0;
   rgColumnDescs[0].dbcid.eKind = DBKIND_NAME;
   rgColumnDescs[0].dbcid.uName.pwszName = L"datecol";
   rgColumnDescs[0].wType = DBTYPE_DBDATE;
   rgColumnDescs[0].bPrecision = 0;
   rgColumnDescs[0].bScale = 0;

   rgColumnDescs[1].pwszTypeName = L"time";
   rgColumnDescs[1].pTypeInfo = NULL;
   rgColumnDescs[1].rgPropertySets = NULL;
   rgColumnDescs[1].pclsid = NULL;
   rgColumnDescs[1].cPropertySets = 0;
   rgColumnDescs[1].ulColumnSize = 0;
   rgColumnDescs[1].dbcid.eKind = DBKIND_NAME;
   rgColumnDescs[1].dbcid.uName.pwszName = L"timecol";
   rgColumnDescs[1].wType = DBTYPE_DBTIME2;
   rgColumnDescs[1].bPrecision = 0;
   rgColumnDescs[1].bScale = 7;

   rgColumnDescs[2].pwszTypeName = L"datetime2";
   rgColumnDescs[2].pTypeInfo = NULL;
   rgColumnDescs[2].rgPropertySets = NULL;
   rgColumnDescs[2].pclsid = NULL;
   rgColumnDescs[2].cPropertySets = 0;
   rgColumnDescs[2].ulColumnSize = 0;
   rgColumnDescs[2].dbcid.eKind = DBKIND_NAME;
   rgColumnDescs[2].dbcid.uName.pwszName = L"datetime2col";
   rgColumnDescs[2].wType = DBTYPE_DBTIMESTAMP;
   rgColumnDescs[2].bPrecision = 0;
   rgColumnDescs[2].bScale = 7;

   rgColumnDescs[3].pwszTypeName = L"datetimeoffset";
   rgColumnDescs[3].pTypeInfo = NULL;
   rgColumnDescs[3].rgPropertySets = NULL;
   rgColumnDescs[3].pclsid = NULL;
   rgColumnDescs[3].cPropertySets = 0;
   rgColumnDescs[3].ulColumnSize = 0;
   rgColumnDescs[3].dbcid.eKind = DBKIND_NAME;
   rgColumnDescs[3].dbcid.uName.pwszName = L"datetimeoffsetcol";
   rgColumnDescs[3].wType = DBTYPE_DBTIMESTAMPOFFSET;
   rgColumnDescs[3].bPrecision = 0;
   rgColumnDescs[3].bScale = 7;

   hr = pUnkDataSource->QueryInterface(IID_ITableDefinition, (void**)&pITableDefinition);   
   hr = pITableDefinition->CreateTable(NULL, pTableID, sc_cCol, rgColumnDescs, IID_IRowset, 0, NULL, &pTableID, ppUnkRowset); 

   // Ignore the case where the table already exists
   if (DB_E_DUPLICATETABLEID == hr)
      hr = S_OK;

   if (pITableDefinition)
      pITableDefinition->Release();

   return hr;
}

HRESULT myTableChange(IOpenRowset * pIOpenRowset, DBID * pTableID, IUnknown ** ppUnkRowset) {
   HRESULT hr;
   IRowsetChange * pIRowsetChange = NULL;
   IAccessor * pIAccessor = NULL;
   HACCESSOR hAccessor = NULL;
   HROW hRow = NULL;

   static const DBCOUNTITEM sc_cCol = 4;

   // Bindings and values
   DateTimeTypeEx rgDttEx[sc_cCol] = {0};
   DBBINDING rgBindings[sc_cCol] = {0};
   DBBINDSTATUS rgStatus[sc_cCol] = {0};

   TypePrecScalEx rgTpsEx[sc_cCol] = { 
      DBTYPE_DBDATE, 0, 0, L"DATE", sizeof(DBDATE),
      DBTYPE_DBTIME2, 0, 7, L"TIME", sizeof(DBTIME2),
      DBTYPE_DBTIMESTAMP, 0, 7, L"DATETIME2", sizeof(DBTIMESTAMP),
      DBTYPE_DBTIMESTAMPOFFSET, 0, 7, L"DATETIMEOFFSET", sizeof(DBTIMESTAMPOFFSET)  
   };

   // Open IRowsetChange interface on existing table
   hr = pIOpenRowset->OpenRowset(NULL, pTableID, NULL, IID_IRowsetChange, 0, NULL, (IUnknown**)&pIRowsetChange);   

   // Prepare bindings
   for (unsigned int i = 0; i < sc_cCol; i++) {
      rgBindings[i].iOrdinal = i+1;
      rgBindings[i].obValue = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);     
      rgBindings[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindings[i].obStatus = (i * sizeof(DateTimeTypeEx));

      rgBindings[i].pTypeInfo = NULL;
      // rgBindings[i].pObject not used
      rgBindings[i].pBindExt = NULL;
      rgBindings[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindings[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindings[i].eParamIO = DBPARAMIO_NOTPARAM ;
      rgBindings[i].cbMaxLen = 0;   // ignored for fixed length types (sizeof(DBTIMESTAMP))
      rgBindings[i].dwFlags = 0;
      rgBindings[i].wType = rgTpsEx[i].wType;
      rgBindings[i].bPrecision = rgTpsEx[i].bPrec;
      rgBindings[i].bScale = rgTpsEx[i].bScale;
   }

   // Create accessors
   hr = pIRowsetChange->QueryInterface(IID_IAccessor, (void**)&pIAccessor);
   hr =  pIAccessor->CreateAccessor (DBACCESSOR_ROWDATA, sc_cCol, rgBindings, 0, &hAccessor, rgStatus); 

   // Set value in preparation for inserting a new row
   rgDttEx[0].length = sizeof(DBDATE);
   rgDttEx[0].d.year = 1979;
   rgDttEx[0].d.month = 4;
   rgDttEx[0].d.day = 1;

   rgDttEx[1].length = sizeof(DBTIME2);
   rgDttEx[1].t.hour = 2;
   rgDttEx[1].t.minute = 3;
   rgDttEx[1].t.second = 5;
   rgDttEx[1].t.fraction = 800000;

   rgDttEx[2].length = sizeof(DBTIMESTAMP);
   rgDttEx[2].ts.year = 1776;
   rgDttEx[2].ts.month = 7;
   rgDttEx[2].ts.day = 4;
   rgDttEx[2].ts.hour = 21;
   rgDttEx[2].ts.minute = 39;
   rgDttEx[2].ts.second = 59;
   rgDttEx[2].ts.fraction = 5000000;

   rgDttEx[3].length = sizeof(DBTIMESTAMPOFFSET);
   rgDttEx[3].tso.year = 1979;
   rgDttEx[3].tso.month = 4;
   rgDttEx[3].tso.day = 1;
   rgDttEx[3].tso.hour = 2;
   rgDttEx[3].tso.minute = 3;
   rgDttEx[3].tso.second = 5;
   rgDttEx[3].tso.fraction = 0;
   rgDttEx[3].tso.timezone_hour = -5;
   rgDttEx[3].tso.timezone_minute = 0;

   hr = pIRowsetChange->InsertRow(NULL, hAccessor, rgDttEx, &hRow);   

   if (pIRowsetChange)
      pIRowsetChange->Release();

   if (pIAccessor)
      pIAccessor->Release();

   return hr;
}

HRESULT myTableRead(IOpenRowset * pIOpenRowset, DBID * pTableID, IUnknown ** ppUnkRowset) {
   HRESULT  hr;
   IRowset * pIRowset = NULL;
   IAccessor * pIAccessor = NULL;
   HACCESSOR hAccessor = NULL;
   HACCESSOR hAccessorStr = NULL;
   HACCESSOR hAccessorWstr = NULL;
   static const DBROWCOUNT sc_cRows = 1;
   HROW * rghRow = NULL;
   DBCOUNTITEM cRowsObtained = 0;

   // static const DBORDINAL sc_cCol = 4;
   static const DBCOUNTITEM sc_cCol = 4;

   // Bindings and values
   DateTimeTypeEx rgDttEx[sc_cCol] = {0};
   DBBINDING rgBindings[sc_cCol] = {0};
   DBBINDSTATUS rgStatus[sc_cCol] = {0};
   DBBINDING rgBindingsStr[sc_cCol] = {0};
   DBBINDING rgBindingsWstr[sc_cCol] = {0};

   TypePrecScalEx rgTpsEx[sc_cCol] = { 
      DBTYPE_DBDATE, 0, 0, L"DATE", sizeof(DBDATE),
      DBTYPE_DBTIME2, 0, 0, L"TIME", sizeof(DBTIME2),
      DBTYPE_DBTIMESTAMP, 0, 0, L"DATETIME2", sizeof(DBTIMESTAMP),
      DBTYPE_DBTIMESTAMPOFFSET, 0, 0, L"DATETIMEOFFSET", sizeof(DBTIMESTAMPOFFSET)
   };

   printf ("%d = sizeof(DateTimeTypeEx)\n", sizeof(DateTimeTypeEx));

   // Open IRowsetChange interface on existing table
   hr = pIOpenRowset->OpenRowset(NULL, pTableID, NULL, IID_IRowset, 0, NULL, (IUnknown**)&pIRowset);   

   // Prepare bindings
   for (unsigned int i = 0; i < 4; i++) {
      rgBindings[i].iOrdinal = i+1;
      rgBindingsStr[i].iOrdinal = i+1;
      rgBindingsWstr[i].iOrdinal = i+1;

      rgBindings[i].obValue = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);     
      rgBindings[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindingsStr[i].obValue = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);  
      rgBindingsWstr[i].obValue = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, t);;
      rgBindings[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindingsStr[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindingsWstr[i].obLength = (i * sizeof(DateTimeTypeEx)) + offsetof(DateTimeTypeEx, length);
      rgBindings[i].obStatus = (i * sizeof(DateTimeTypeEx));
      rgBindingsStr[i].obStatus = (i * sizeof(DateTimeTypeEx));
      rgBindingsWstr[i].obStatus = (i * sizeof(DateTimeTypeEx));
      rgBindings[i].pTypeInfo = NULL;
      rgBindingsStr[i].pTypeInfo = NULL;
      rgBindingsWstr[i].pTypeInfo = NULL;
      // rgBindings[i].pObject not used
      rgBindings[i].pBindExt = NULL;
      rgBindingsStr[i].pBindExt = NULL;
      rgBindingsWstr[i].pBindExt = NULL;
      rgBindings[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindingsStr[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindingsWstr[i].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;
      rgBindings[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindingsStr[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindingsWstr[i].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
      rgBindings[i].eParamIO = DBPARAMIO_NOTPARAM ;
      rgBindingsStr[i].eParamIO = DBPARAMIO_NOTPARAM ;
      rgBindingsWstr[i].eParamIO = DBPARAMIO_NOTPARAM ;
      rgBindings[i].cbMaxLen = 0;   // ignored for fixed length types
      rgBindingsStr[i].cbMaxLen = sc_cchStrLen; 
      rgBindingsWstr[i].cbMaxLen = sizeof(WCHAR)*sc_cchStrLen; 
      rgBindings[i].dwFlags = 0;
      rgBindingsStr[i].dwFlags = 0;
      rgBindingsWstr[i].dwFlags = 0;
      rgBindings[i].wType = rgTpsEx[i].wType;
      rgBindingsStr[i].wType = DBTYPE_STR;
      rgBindingsWstr[i].wType = DBTYPE_WSTR;
      rgBindings[i].bPrecision = rgTpsEx[i].bPrec;
      rgBindingsStr[i].bPrecision = 0;
      rgBindingsWstr[i].bPrecision = 0;
      rgBindings[i].bScale = rgTpsEx[i].bScale;
      rgBindingsStr[i].bScale = 0;
      rgBindingsWstr[i].bScale = 0;
   }

   // Create accessors
   hr = pIRowset->QueryInterface(IID_IAccessor, (void**)&pIAccessor);
   hr =  pIAccessor->CreateAccessor (DBACCESSOR_ROWDATA, sc_cCol, rgBindings, 0, &hAccessor, rgStatus); 
   hr =  pIAccessor->CreateAccessor (DBACCESSOR_ROWDATA, sc_cCol, rgBindingsStr, 0, &hAccessorStr, rgStatus); 
   hr =  pIAccessor->CreateAccessor (DBACCESSOR_ROWDATA, sc_cCol, rgBindingsWstr, 0, &hAccessorWstr, rgStatus); 
   hr = pIRowset->GetNextRows(DB_NULL_HCHAPTER, 0, sc_cRows, &cRowsObtained, &rghRow);
   hr = pIRowset->GetData(rghRow[0], hAccessor, rgDttEx);
   hr = pIRowset->GetData(rghRow[0], hAccessorStr, rgDttEx);
   hr = pIRowset->GetData(rghRow[0], hAccessorWstr, rgDttEx);   

   if (pIRowset)
      pIRowset->Release();

   if (pIAccessor)
      pIAccessor->Release();

   return hr;
}

int main() {
   HRESULT hr = S_OK;
   IDBInitialize * pIDBInitialize = NULL;
   IDBCreateSession * pIDBCreateSession = NULL;
   ISSCommandWithParameters * pIDBCreateCommand = NULL;
   IOpenRowset * pIOpenRowset = NULL;
   IRowset * pIRowset = NULL;
   DBID tableID = {0};

   hr = InitializeAndEstablishConnection((IUnknown**)&pIDBInitialize);
   hr = myCreateSession((IUnknown*)pIDBInitialize, IID_IDBCreateCommand, (IUnknown**)&pIDBCreateSession);
   hr = myTableDefinition(pIDBCreateSession, &tableID, (IUnknown**)&pIRowset);
   hr = myCreateSession((IUnknown*)pIDBInitialize, IID_IOpenRowset, (IUnknown**)&pIOpenRowset);
   hr = myTableChange(pIOpenRowset, &tableID, (IUnknown**)&pIRowset);
   hr = myTableRead(pIOpenRowset, &tableID, (IUnknown**)&pIRowset);
   hr = myCreateCommand((IUnknown*)pIDBCreateSession, (IUnknown**)&pIDBCreateCommand);
   hr = myExecuteCommand(pIDBCreateCommand,  0, NULL, (IUnknown**)&pIRowset);

   if (pIDBInitialize)
      pIDBInitialize->Release();

   if (pIDBCreateSession)
      pIDBCreateSession->Release();

   if (pIDBCreateCommand)
      pIDBCreateCommand->Release();

   if (pIRowset)
      pIRowset->Release();
}

IF EXISTS (SELECT name FROM sysobjects WHERE name = 'sp_datetimetypes')
     DROP PROCEDURE sp_datetimetypes
Condividi tramite

Utilizzare le caratteristiche avanzate di data e ora (OLE DB)

Esempio

Risorse aggiuntive
