큰 CLR UDT 사용(OLE DB)
이 예제에서는 결과 집합에서 큰 사용자 정의 형식의 행을 인출하는 방법을 보여 줍니다. 자세한 내용은 큰 CLR 사용자 정의 형식(OLE DB)을 참조하십시오. 이 예제는 SQL Server 2008 이상에서만 작동합니다.
예
이 예제에는 두 개의 프로젝트가 포함되어 있습니다. 첫 번째 프로젝트는 C# 원본 코드에서 어셈블리(DLL)를 만듭니다. 이 어셈블리에는 CLR 유형이 포함되어 있습니다. 테이블이 데이터베이스에 추가됩니다. 테이블의 열은 어셈블리에 정의된 유형으로 지정됩니다. 기본적으로 이 예제에서는 master 데이터베이스를 사용합니다. 두 번째 프로젝트는 테이블에서 데이터를 읽는 네이티브 C 응용 프로그램입니다.
첫 번째(C#) 코드 목록을 DLL로 컴파일합니다. 그리고 나서 DLL을 C 드라이브의 루트 디렉터리에 복사합니다.
두 번째(Transact-SQL) 코드 목록을 실행하여 어셈블리를 master 데이터베이스에 추가합니다.
ole32.lib oleaut32.lib를 사용하여 컴파일하고 세 번째(C++) 코드 목록을 실행합니다. 이 응용 프로그램은 컴퓨터의 기본 SQL Server 인스턴스에 연결됩니다. 일부 Windows 운영 체제에서는 (localhost) 또는 (local)을 해당 SQL Server 인스턴스의 이름으로 변경해야 합니다. 명명된 인스턴스에 연결하려면 연결 문자열을 L"(local)"에서 L"(local)\\name"으로 변경합니다. 여기서 name은 명명된 인스턴스입니다. 기본적으로 SQL Server Express는 명명된 인스턴스에 설치됩니다. INCLUDE 환경 변수에 sqlncli.h가 들어 있는 디렉터리를 포함해야 합니다.
네 번째(Transact-SQL) 코드 목록을 실행하여 master 데이터베이스의 어셈블리를 삭제합니다.
// 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