Gunakan UDT CLR Besar di SQL Server Native Client (OLE DB)

Berlaku untuk:SQL ServerAzure SQL DatabaseAzure SQL Managed InstanceAzure Synapse Analytics AnalyticsPlatform System (PDW)

Sampel ini menunjukkan cara mengambil baris dengan jenis besar yang ditentukan pengguna dari kumpulan hasil. Untuk informasi selengkapnya, lihat Jenis Yang Ditentukan Pengguna CLR Besar (OLE DB). Sampel ini berfungsi dengan SQL Server 2008 (10.0.x) atau yang lebih baru.

Contoh

Sampel ini berisi dua proyek. Satu proyek membuat assembly (DLL) dari kode sumber C#. Rakitan ini berisi jenis CLR. Tabel akan ditambahkan ke database. Kolom dalam tabel akan berjenis yang ditentukan dalam rakitan. Secara default, sampel ini akan menggunakan database master. Proyek kedua adalah aplikasi C asli yang membaca data dari tabel.

Kompilasi daftar kode pertama (C#) ke DLL. Kemudian, salin DLL ke direktori akar drive C.

Jalankan daftar kode kedua (Transact-SQL) untuk menambahkan rakitan ke database master.

Kompilasi dengan ole32.lib oleaut32.lib dan jalankan daftar kode ketiga (C++). Aplikasi ini tersambung ke instans SQL Server default komputer Anda. Pada beberapa sistem operasi Windows, Anda harus mengubah (localhost) atau (lokal) ke nama instans SQL Server Anda. Untuk menyambungkan ke instans bernama, ubah string koneksi dari L"(local)" ke L"(local)\\name", di mana nama adalah instans bernama. Secara default, SQL Server Express menginstal ke instans bernama. Pastikan variabel lingkungan INCLUDE Anda menyertakan direktori yang berisi sqlncli.h.

Jalankan daftar kode keempat (Transact-SQL) untuk menghapus rakitan ke database master.

// compile with: /target: library  
using System;  
using System.Data;  
using System.Data.SqlTypes;  
using Microsoft.SqlServer.Server;  
using System.Text;  
  
[assembly: System.CLSCompliantAttribute(true)]  
[Serializable]  
[Microsoft.SqlServer.Server.SqlUserDefinedType(Format.UserDefined, IsFixedLength = false, MaxByteSize = -1, IsByteOrdered = true)]  
public class LargeStringUDT : INullable, IBinarySerialize {  
    private bool _isNull;  
    private string _largeString;  
  
    public bool IsNull {  
        get {  
            return (_isNull);  
        }  
    }  
  
    public static LargeStringUDT Null {  
        get {  
            LargeStringUDT lsUDT = new LargeStringUDT();  
            lsUDT._isNull = true;  
            return lsUDT;  
        }  
    }  
  
    public override string ToString() {  
        if (IsNull)  
            return "NULL";  
        else  
            return _largeString;  
    }  
  
    [SqlMethod(OnNullCall = false)]  
    public static LargeStringUDT Parse(SqlString s) {  
        if (s.IsNull)  
            return Null;  
  
        LargeStringUDT lsUDT = new LargeStringUDT();  
        lsUDT._largeString = s.Value;  
        return lsUDT;  
    }  
  
    public String LargeString {  
        get {  
            return _largeString;  
        }  
  
        set {  
            _largeString = value;  
        }  
    }  
  
    public void Read(System.IO.BinaryReader r) {  
        _isNull = r.ReadBoolean();  
        if (!_isNull)  
            _largeString = new String(r.ReadChars(r.ReadInt32()));  
    }  
  
    public void Write(System.IO.BinaryWriter w) {  
        w.Write(_isNull);  
        if (!_isNull) {  
            w.Write(_largeString.Length);  
            for (int i = 0; i < _largeString.Length; ++i)  
                w.Write(_largeString[i]);  
        }  
    }  
}  

USE [MASTER]  
GO  
  
CREATE ASSEMBLY LargeStringUDT  
FROM 'C:\LargeStringUDT.dll'  
WITh PERMISSION_SET=SAFE;  
GO  
  
CREATE TYPE dbo.LargeStringUDT   
EXTERNAL NAME LargeStringUDT.[LargeStringUDT];  
GO  
  
CREATE TABLE dbo.LargeStringUDTs  
(ID int IDENTITY(1,1) PRIMARY KEY, LargeString LargeStringUDT)  
GO  
  
INSERT INTO dbo.LargeStringUDTs (LargeString) VALUES (CONVERT(LargeStringUDT, 'This is the first string'));  
INSERT INTO dbo.LargeStringUDTs (LargeString) VALUES (CONVERT(LargeStringUDT, 'This is the second string'));  
INSERT INTO dbo.LargeStringUDTs (LargeString) VALUES (Convert(LargeStringUDT, 'This is the third string'));  
GO  

// compile with: ole32.lib oleaut32.lib  
// Gives length of an array  
#define ARRAY_SIZE(rgArray) (sizeof(rgArray)/sizeof(*rgArray))  
#define NUMELEM(rgArray) ARRAY_SIZE(rgArray)  
  
#define DBINITCONSTANTS  
#define INITGUID  
  
#define OLEDBVER 0x0250   // to include correct interfaces  
  
#define ROUND_UP_MINIMUM 8  
  
#define ROUND_UP(valueToRound) \  
   (((valueToRound) + (ROUND_UP_MINIMUM - 1)) & ~(ROUND_UP_MINIMUM - 1))  
  
#include <stdio.h>  
#include <tchar.h>  
#include <stddef.h>  
#include <windows.h>  
#include <iostream>  
#include <oledb.h>  
#include <SQLNCLI.h>  
  
using namespace std;  
  
// Arrangement of column data when standard rowbuffer layout is used.  
struct COLUMNDATA {  
   DBLENGTH dwLength;   // length of data (not space allocated)  
   DBSTATUS dwStatus;   // status of column  
#ifdef _WIN64  
   // rgbData needs to be COLUMN_ALIGNVAL byte aligned. This fixes it for 64 bit build.  
   DWORD dwAlign;  
#endif  
   BYTE rgbData[1];   // data here and beyond  
};  
  
int InitializeAndEstablishConnection();  
int ProcessResultSet();  
  
IDBInitialize* pIDBInitialize = NULL;  
IDBProperties* pIDBProperties = NULL;  
IDBCreateSession* pIDBCreateSession = NULL;  
IDBCreateCommand* pIDBCreateCommand = NULL;  
ICommandText* pICommandText = NULL;  
IRowset* pIRowset = NULL;  
IColumnsInfo* pIColumnsInfo = NULL;  
ISequentialStream* pISequentialStream;  
  
DBCOLUMNINFO* pDBColumnInfo = NULL;  
IAccessor* pIAccessor =  NULL;  
DBPROP InitProperties[4];  
DBPROPSET rgInitPropSet[1];  
  
ULONG i, j;  
HRESULT hr;  
DBROWCOUNT cNumRows = 0;  
DBORDINAL lNumCols;  
WCHAR* pStringsBuffer;  
DBBINDING* pBindings;  
HACCESSOR hAccessor;  
DBCOUNTITEM lNumRowsRetrieved;  
HROW hRows[10];  
HROW* pRows = &hRows[0];  
  
int main() {  
   // The command to execute.  
   WCHAR* wCmdString = OLESTR("SELECT ID, LargeString FROM dbo.LargeStringUDTs");  
  
   // Call a function to initialize and establish connection.   
   if (InitializeAndEstablishConnection() == -1) {  
      cout << "Failed to initialize and connect to the server.\n";  
      return -1;  
   }  
  
   // Create a session   
   if (FAILED(pIDBInitialize->QueryInterface( IID_IDBCreateSession, (void**) &pIDBCreateSession))) {  
         cout << "Failed to obtain IDBCreateSession interface.\n";  
         return -1;  
   }  
  
   if (FAILED(pIDBCreateSession->CreateSession( NULL, IID_IDBCreateCommand, (IUnknown**) &pIDBCreateCommand))) {  
         cout << "pIDBCreateSession->CreateSession failed.\n";  
         return -1;  
   }  
  
   // Access the ICommandText interface.  
   if (FAILED(pIDBCreateCommand->CreateCommand( NULL, IID_ICommandText, (IUnknown**) &pICommandText))) {  
         cout << "Failed to access ICommand interface.\n";  
         return -1;  
   }  
  
   // Specify the command text.  
   if (FAILED(pICommandText->SetCommandText(DBGUID_DBSQL, wCmdString))) {  
      cout << "Failed to set command text.\n";  
      return -1;  
   }  
  
   // Execute the command.  
   if (FAILED(hr = pICommandText->Execute( NULL, IID_IRowset, NULL, &cNumRows, (IUnknown **) &pIRowset))) {  
         cout << "Failed to execute command.\n";  
         return -1;  
   }  
  
   // Process the result set.  
   ProcessResultSet();   
  
   pIRowset->Release();  
  
   // release memory.  
   pICommandText->Release();  
   pIDBCreateCommand->Release();  
   pIDBCreateSession->Release();  
  
   if (FAILED(pIDBInitialize->Uninitialize())) {  
      // Uninitialize is not required, but it fails if an interface has not been released.  This can be used for debugging.  
      cout << "Problem uninitializing.\n";  
   }  
  
   pIDBInitialize->Release();  
   CoUninitialize();  
};  
  
int InitializeAndEstablishConnection() {      
   CoInitialize(NULL);  
  
   // Obtain access to the SQLNCLI provider.  
   hr = CoCreateInstance( CLSID_SQLNCLI11, NULL, CLSCTX_INPROC_SERVER, IID_IDBInitialize, (void **) &pIDBInitialize);  
  
   if (FAILED(hr)) {  
      printf("Failed to get IDBInitialize interface.\n");  
      return -1;  
   }  
  
   // Initialize the property values needed to establish the connection.  
   for ( i = 0 ; i < 4 ; i++ )  
      VariantInit(&InitProperties[i].vValue);  
  
   // Server name.  
   InitProperties[0].dwPropertyID = DBPROP_INIT_DATASOURCE;  
   InitProperties[0].vValue.vt = VT_BSTR;  
   //InitProperties[0].vValue.bstrVal= SysAllocString(L"(local)\\SQLExpress");  
   InitProperties[0].vValue.bstrVal= SysAllocString(L"(local)");  
   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"master");  
   InitProperties[1].dwOptions = DBPROPOPTIONS_REQUIRED;  
   InitProperties[1].colid = DB_NULLID;  
  
   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;  
  
   // Properties are set, now construct the DBPROPSET structure (rgInitPropSet) 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);  
   if (FAILED(hr)) {  
      cout << "Failed to get IDBProperties interface.\n";  
      return -1;  
   }  
  
   hr = pIDBProperties->SetProperties(1, rgInitPropSet);   
   if (FAILED(hr)) {  
      cout << "Failed to set initialization properties.\n";  
      return -1;  
   }  
  
   pIDBProperties->Release();  
  
   // Now establish the connection to the data source.  
   if (FAILED(pIDBInitialize->Initialize())) {  
      cout << "Problem in establishing connection to the data"  
         "source.\n";  
      return -1;  
   }  
   return 0;  
}  
  
// Retrieve and display data resulting from a query.  
int ProcessResultSet() {  
   // Obtain access to the IColumnInfo interface  
   hr = pIRowset->QueryInterface(IID_IColumnsInfo, (void **)&pIColumnsInfo);  
   if (FAILED(hr)) {  
      cout << "Failed to get IColumnsInfo interface.\n";  
      return -1;  
   }   
  
   // Retrieve the column information.  
   pIColumnsInfo->GetColumnInfo(&lNumCols, &pDBColumnInfo, &pStringsBuffer);  
  
   // Free the columninfo interface.  
   pIColumnsInfo->Release();  
  
   // Create a DBBINDING array.  
   DBBINDING * p = (pBindings = new DBBINDING[lNumCols]);  
   if (!(p /* pBindings = new DBBINDING[lNumCols] */ ))  
      return -1;  
  
   // There are two columns in the table.  
   pBindings[0].iOrdinal = 1;   
   pBindings[0].obValue = 0;  
   pBindings[0].obLength = 0;  
   pBindings[0].obStatus = 0;  
   pBindings[0].pTypeInfo = NULL;  
   pBindings[0].pObject = NULL;  
   pBindings[0].pBindExt = NULL;  
   pBindings[0].dwPart = DBPART_VALUE | DBPART_LENGTH | DBPART_STATUS;  
   pBindings[0].dwMemOwner = DBMEMOWNER_CLIENTOWNED;  
   pBindings[0].eParamIO = DBPARAMIO_NOTPARAM;   // Count 10  
   pBindings[0].cbMaxLen = sizeof(long);  
   pBindings[0].dwFlags = 0;  
   pBindings[0].wType = DBTYPE_I4;  
   pBindings[0].bPrecision = 0;  
   pBindings[0].bScale = 0; //Count 15  
  
   pBindings[1].iOrdinal = 2;   
   pBindings[1].obValue = 0;  
   pBindings[1].obLength = 0;  
   pBindings[1].obStatus = 0;  
   pBindings[1].pTypeInfo = NULL;  
   pBindings[1].pObject = NULL;  
   pBindings[1].pBindExt = NULL;  
   pBindings[1].dwPart = DBPART_VALUE | DBPART_STATUS;  
   pBindings[1].dwMemOwner = DBMEMOWNER_CLIENTOWNED;  
   pBindings[1].eParamIO = DBPARAMIO_NOTPARAM; //Count 10  
   pBindings[1].cbMaxLen = sizeof(IUnknown*);  
   pBindings[1].dwFlags = 0;  
   pBindings[1].wType = DBTYPE_IUNKNOWN;  
   pBindings[1].bPrecision = 0;  
   pBindings[1].bScale = 0; //Count 15  
  
   DBBYTEOFFSET rowSize = 0;  
  
   for (size_t i = 0; i < lNumCols; i++) {  
      pBindings[i].obLength = rowSize + offsetof(COLUMNDATA, dwLength);  
      pBindings[i].obStatus = rowSize + offsetof(COLUMNDATA, dwStatus);  
      pBindings[i].obValue  = rowSize + offsetof(COLUMNDATA, rgbData);  
  
      rowSize += offsetof(COLUMNDATA, rgbData) + pBindings[i].cbMaxLen;  
      rowSize  = ROUND_UP(rowSize);  
   }  
  
   hr = pIRowset->QueryInterface(IID_IAccessor, (void **) &pIAccessor);  
   if (FAILED(hr)) {  
      cout << "Failed to obtain IAccessor interface.\n";  
      return -1;  
   }  
  
   // Create an accessor from the set of bindings (pBindings).  
   pIAccessor->CreateAccessor(DBACCESSOR_ROWDATA, lNumCols, pBindings, 0, &hAccessor, NULL);  
  
   // Print column names.  
   for ( j = 0 ; j < lNumCols ; j++ )  
      printf("%-30S", pDBColumnInfo[j].pwszName);  
  
   printf("\n");   // new line after the column names  
  
   // Get a set of 10 row at a time.  
   pIRowset->GetNextRows( NULL, 0, 10, &lNumRowsRetrieved, &pRows);  
  
   // Allocate space for the row buffer.  
   BYTE * pBuffer = new BYTE[rowSize];  
   if (!(pBuffer /* = new BYTE[rowSize]; */ )) {  
      // Free up all allocated memory.  
      pIAccessor->ReleaseAccessor(hAccessor, NULL);  
      pIAccessor->Release();  
      delete [] pBindings;  
      return 0;  
   }  
  
   // Display the rows.  
   while ( lNumRowsRetrieved > 0 ) {  
      // For each row, print the column data.  
      for ( j = 0 ; j < lNumRowsRetrieved ; j++ ) {  
         // Clear the buffer.  
         memset(pBuffer, 0, rowSize);  
  
         // Get the row data values.  
         pIRowset->GetData(hRows[j], hAccessor, pBuffer);  
  
         // Print the first column  
         printf("%-25d", *((long*)(*(&pBuffer) + pBindings[0].obValue)));  
         ULONG dwStatus = *((ULONG*) (pBuffer + pBindings[1].obStatus));  
  
         if (dwStatus == DBSTATUS_S_ISNULL) {  
            // Process NULL data  
         }  
  
         else if (dwStatus == DBSTATUS_S_OK) {  
            HRESULT hrStreamRead = S_OK;  
            ULONG cbRead = 0;  
            BYTE DataBuff[1024];  
  
            memset(DataBuff, 0, 1024);  
  
            pISequentialStream = *((ISequentialStream**)(pBuffer + pBindings[1].obValue));  
  
            do {  
               hrStreamRead = pISequentialStream->Read(DataBuff, sizeof(DataBuff), &cbRead);  
               if (SUCCEEDED(hrStreamRead)) {  
                  // First byte indicate the value for IsNull property and the next four bytes   
                  // indicate the length of the string. So we start from the fifth byte.  
                  for (ULONG i = 5; i < cbRead; i++)  
                     putchar((char)DataBuff[i]);  
  
                  printf("\n");  
               }  
            }  
            while (hrStreamRead != S_FALSE && cbRead == sizeof(DataBuff));  
  
            pISequentialStream->Release();  
         }  
         else  
            // Process error from GetData.  
            cout << "Failed to GetData.\n";  
  
      } // for  
  
      // Release the rows retrieved.  
      pIRowset->ReleaseRows(lNumRowsRetrieved, hRows, NULL, NULL, NULL);  
  
      // Get the next 10 rows.  
      pIRowset->GetNextRows(NULL, 0, 10, &lNumRowsRetrieved, &pRows);  
   } // while  
  
   // Free up all allocated memory.  
   delete [] pBuffer;  
   pIAccessor->ReleaseAccessor(hAccessor, NULL);  
   pIAccessor->Release();  
   delete [] pBindings;  
  
   return 0;  
}  

USE [MASTER]  
IF EXISTS (SELECT * FROM sys.objects WHERE name = 'LargeStringUDTs')  
   DROP TABLE LargeStringUDTs  
GO  
  
IF EXISTS (SELECT * FROM sys.types WHERE name = 'LargeStringUDT')  
   DROP TYPE dbo.LargeStringUDT  
GO  
  
IF EXISTS (SELECT * FROM sys.assemblies WHERE name = 'LargeStringUDT')  
   DROP ASSEMBLY LargeStringUDT  
GO