catsets.cpp

一个介绍Odbc的详细例子

// catsets.cpp - recordsets that describe the type info
//
// This is a part of the Microsoft Foundation Classes C++ library.
// Copyright (C) 1992-1998 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Microsoft Foundation Classes Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Microsoft Foundation Classes product.

#include "stdafx.h"
#include "catsets.h"

/////////////////////////////////////////////////////////////////////////////
// CGetTypeInfo

CGetTypeInfo::CGetTypeInfo(CDatabase* pDatabase)
	: CRecordset(pDatabase)
{
	m_strTypeName           = _T("");
	m_fDataType             = 0;
	m_nPrecision            = 0;
	m_strLiteralPrefix      = _T("");
	m_strLiteralSuffix      = _T("");
	m_strCreateParams       = _T("");
	m_fNullable             = 0;
	m_bCaseSensitive        = 0;
	m_fSearchable           = 0;
	m_fUnsignedAttribute    = 0;
	m_bMoney                = 0;
	m_fAutoIncrement        = 0;
	m_strLocalTypeName      = _T("");
	m_nMinimumScale         = 0;
	m_nMaximumScale         = 0;
	m_nFields = 15;
}

BOOL CGetTypeInfo::Open(short fSqlType,
	UINT nOpenType)
{
	RETCODE nRetCode;
	UWORD   bFunctionExists;

	// make suer SQLGetTypeInfo exists
	AFX_SQL_SYNC(::SQLGetFunctions(m_pDatabase->m_hdbc,
		SQL_API_SQLGETTYPEINFO,&bFunctionExists));
	if (!Check(nRetCode) || !bFunctionExists)
	{
		if (!bFunctionExists)
			TRACE(_T("SQLGetTypeInfo not supported\n"));
		return FALSE;
	}

	// Cache state info and allocate hstmt
	SetState(nOpenType, NULL, readOnly);
	if(!AllocHstmt())
		return FALSE;

	TRY
	{
		OnSetOptions(m_hstmt);

		// Build SQL and prep/execute or just execute direct
		AllocStatusArrays();

		// call the ODBC function
		AFX_SQL_ASYNC(this,::SQLGetTypeInfo(m_hstmt,fSqlType));
		if (!Check(nRetCode))
			ThrowDBException(nRetCode,m_hstmt);

		// Allocate memory and cache info
		AllocAndCacheFieldInfo();
		AllocRowset();

		// Fetch the first row of data
		MoveNext();

		// If EOF, then result set empty, so set BOF as well
		m_bBOF = m_bEOF;
	}
	CATCH_ALL(e)
	{
		Close();
		THROW_LAST();
	}
	END_CATCH_ALL

	return TRUE;
}

void CGetTypeInfo::DoFieldExchange(CFieldExchange* pFX)
{
	pFX->SetFieldType(CFieldExchange::outputColumn);
	RFX_Text(pFX, _T("TYPE_NAME"), m_strTypeName);
	RFX_Int(pFX, _T("DATA_TYPE"), m_fDataType);
	RFX_Long(pFX, _T("PRECISION"), m_nPrecision);
	RFX_Text(pFX, _T("LITERAL_PREFIX"), m_strLiteralPrefix);
	RFX_Text(pFX, _T("LITERAL_SUFFIX"), m_strLiteralSuffix);
	RFX_Text(pFX, _T("CREATE_PARAMS"), m_strCreateParams);
	RFX_Int(pFX, _T("NULLABLE"), m_fNullable);
	RFX_Int(pFX, _T("CASE_SENSITIVE"), m_bCaseSensitive);
	RFX_Int(pFX, _T("SEARCHABLE"), m_fSearchable);
	RFX_Int(pFX, _T("UNSIGNED_ATTRIBUTE"), m_fUnsignedAttribute);
	RFX_Int(pFX, _T("MONEY"), m_bMoney);
	RFX_Int(pFX, _T("AUTO_INCREMENT"), m_fAutoIncrement);
	RFX_Text(pFX, _T("LOCAL_TYPE_NAME"), m_strLocalTypeName);
	RFX_Int(pFX, _T("MINIMUM_SCALE"), m_nMinimumScale);
	RFX_Int(pFX, _T("MAXIMUM_SCALE"), m_nMaximumScale);
}