Usar UDT de CLR de gran tamaño (OLE DB)
Se aplica a: 
SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)
En este ejemplo se muestra cómo capturar filas con tipos definidos por el usuario grandes de un conjunto de resultados. Para más información, consulte Tipos grandes definidos por el usuario de CLR (OLE DB). Este ejemplo funciona con SQL Server 2008 (10.0.x) y versiones posteriores.
Ejemplo
Este ejemplo contiene dos proyectos. Un proyecto crea un ensamblado (DLL) a partir de código fuente de C#. Este ensamblado contiene el tipo CLR. Se agregará una tabla a la base de datos. Una columna de la tabla será de un tipo definido en el ensamblado. De forma predeterminada, en este ejemplo se usará la base de datos maestra. El segundo proyecto es una aplicación de C nativa que lee datos de la tabla.
Compile la primera lista de código (C#) a una DLL. A continuación, copie la DLL en el directorio raíz de la unidad C.
Ejecute la segunda lista de código (Transact-SQL) para agregar el ensamblado a la base de datos maestra.
Compile con ole32.lib oleaut32.lib y ejecute la tercera lista de código (C++). Esta aplicación se conecta a la instancia predeterminada de SQL Server del equipo. En algunos sistemas operativos Windows, deberá cambiar (localhost) o (local) al nombre de la instancia de SQL Server . Para conectarse a una instancia con nombre, cambie la cadena de conexión de L"(local)" a L"(local)\\nombre", donde "nombre" es la instancia con nombre. De forma predeterminada, SQL Server Express se instala en una instancia con nombre. Asegúrese de que en la variable de entorno INCLUDE se incluya el directorio que contiene msoledbsql.h.
Ejecute la cuarta lista de código (Transact-SQL) para eliminar el ensamblado de la base de datos maestra.
// 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 <msoledbsql.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 MSOLEDBSQL provider.
hr = CoCreateInstance( CLSID_MSOLEDBSQL, 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