odbcrecordset.h

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#ifndef __ODBCRECORDSET_H__
#define __ODBCRECORDSET_H__

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

/*************************************************************************
 FILE :		  ODBCRecordset.h

 Author :	  Stefan Tchekanov  ([e-mail])

 Description: CODBCRecordset and CDBField classes definition.

			  CODBCRecordset extends CRecordset in a way it handles
			  an array of CDBField objects that are mapped to the
			  corresponding recordset columns. It uses CRecordset
			  data exchange mechanism. You would use CODBCRecordset
			  in a similar way as you would use CRecordset subclasses
			  created by ClassWizard except CODBCRecordset does 
			  not have hardcoded the number and the type of database 
			  fields.
			  Added some functionality for easy data retrieval.

			  CDBField extends CDBVariant with appropriate
			  assignment operators and some other useful methods.

Copyright(c) 1998,1999,2000
by Stefan Tchekanov ([e-mail])

This code may be used in compiled form in any way you desire. This
file may be redistributed unmodified by any means PROVIDING it is 
not sold for profit without the authors written consent, and 
providing that this notice and the authors name is included. If 
the source code in this file is used in any commercial application 
then a simple email to the author would be nice.

This file is provided "as is" with no expressed or implied warranty.
The author accepts no liability if it causes any damage.

*************************************************************************/
/* #    Revisions    # */


/////////////////////////////////////////////////////////////////////////////

#include <afxdb.h>
#include <afxtempl.h>

/////////////////////////////////////////////////////////////////////////////
//	CDBField class is extension to CDBVariant.
//	supports copy constructor and many other useful features
/////////////////////////////////////////////////////////////////////////////

class	CDBField : public CDBVariant {

//	Constructors are private to avoid instantiation
//	except by CODBCRecordset
private:
	CDBField();
	CDBField( const CDBField& dbv );
	
	CDBField& operator =( const CDBField& dbv );

	virtual ~CDBField();


public:
	//	Assignment operators


	CDBField& operator =( const bool bVal );
	CDBField& operator =( const char chVal );
	CDBField& operator =( const unsigned char chVal );
	CDBField& operator =( const short sVal );
	CDBField& operator =( const int iVal );
	CDBField& operator =( const long lVal );
	CDBField& operator =( const float fVal );
	CDBField& operator =( const double fVal );
	CDBField& operator =( const COleDateTime& dtVal );
	CDBField& operator =( const CString& cVal );
	CDBField& operator =( const LPCTSTR szVal );



	//	Get the bool value. Do appropriate conversion.
	bool			AsBool()	const;
	//	Get the unsigned char value. Do appropriate conversion.
	unsigned char	AsChar()	const;
	//	Get the short value. Do appropriate conversion.
	short			AsShort()	const;
	//***	Get the int value which is equal to long value. Do appropriate conversion.
	int				AsInt()		const;
	//	Get the long value. Do appropriate conversion.
	long			AsLong()	const;
	//	Get the float value. Do appropriate conversion.
	float			AsFloat()	const;
	//	Get the double value. Do appropriate conversion.
	double			AsDouble()	const;
	//	Get the date and time value. Do appropriate conversion.
	COleDateTime	AsDate()	const;
	//	Get the CString value. Do appropriate conversion.
	CString			AsString()	const;
	//	Get the long binary value. Do appropriate conversion.
	CLongBinary*	AsBinary()	const;


	//	Data type conversion operators

	operator	bool() const;
	operator	unsigned char() const;
	operator	short() const;
	operator	int() const;
	operator	long() const;
	operator	float() const;
	operator	double() const;
	operator	COleDateTime() const;
	operator	CString() const;
	operator	CLongBinary*() const;

	//	Field type query methods

	bool	IsNull()	const	{ return m_bIsNull || m_dwType == DBVT_NULL; };
	bool	IsBool()	const	{ return m_dwType == DBVT_BOOL; };
	bool	IsChar()	const	{ return m_dwType == DBVT_UCHAR; };
	bool	IsShort()	const	{ return m_dwType == DBVT_SHORT; };
	bool	IsInt()		const	{ return m_dwType == DBVT_LONG; };
	bool	IsLong()	const	{ return m_dwType == DBVT_LONG; };
	bool	IsFloat()	const	{ return m_dwType == DBVT_SINGLE; };
	bool	IsDouble()	const	{ return m_dwType == DBVT_DOUBLE; };
	bool	IsNumber()	const	{ return IsShort() || IsLong() || IsFloat() || IsDouble(); };
	bool	IsDate()	const	{ return m_dwType == DBVT_DATE; };
	bool	IsString()	const	{ return m_dwType == DBVT_STRING; };
	bool	IsBinary()	const	{ return m_dwType == DBVT_BINARY; };

	//	Get the field name
	const	CString&	GetName()	const;

private:
	bool		m_bIsNull;	//	If this field contain a NULL value
	CString		m_cName;	//	Contain the field (column) name
	
	void	SetNull( bool bIsNull )	{ m_bIsNull = bIsNull; };

	friend	class	CODBCRecordset;
};
/////////////////////////////////////////////////////////////////////////////
inline
const	CString&	CDBField::GetName()	const {
	return	m_cName;
}

inline
CDBField::operator	bool() const {
	return	AsBool();
}
inline
CDBField::operator	unsigned char() const {
	return	AsChar();
}
inline
CDBField::operator	short() const {
	return	AsShort();
}
inline
CDBField::operator	int() const {
	return	AsInt();
}
inline
CDBField::operator	long() const {
	return	AsLong();
}
inline
CDBField::operator	float() const {
	return	AsFloat();
}
inline
CDBField::operator	double() const {
	return	AsDouble();
}
inline
CDBField::operator	COleDateTime() const {
	return	AsDate();
}
inline
CDBField::operator	CString() const {
	return	AsString();
}
inline
CDBField::operator	CLongBinary*() const {
	return	NULL;
}
/////////////////////////////////////////////////////////////////////////////



/////////////////////////////////////////////////////////////////////////////
//	CODBCRecordset
/////////////////////////////////////////////////////////////////////////////

class	CODBCRecordset : public CRecordset
{
public:
	// Our constructor uses CRecordset constructor
	CODBCRecordset( CDatabase* pDatabase = NULL );
	virtual	~CODBCRecordset();

	virtual	BOOL	Open( LPCTSTR lpszSQL, 
						  UINT nOpenType = AFX_DB_USE_DEFAULT_TYPE,
						  DWORD dwOptions = 0 );

	virtual	void	Move( long nRows, WORD wFetchType = SQL_FETCH_RELATIVE );// throw( CDBException, CMemoryException );


	//	Number of fields could be get by 
	//	CRecordset::GetODBCFieldCount() method


	//	New functions:

	//	Get the field ID by name - case insensitive
	//	CRecordset::GetFieldIndexByName() works, 
	//	but is case sensitive
	int			GetFieldID( LPCTSTR szName );
	//	Get the field name by ID
	CString		GetFieldName( int nID );


	//	Gets a field by name
	CDBField&	Field( LPCTSTR szName );
	//	Gets a field by number
	CDBField&	Field( int nField );

	//	Gets a field by name
	CDBField&	operator()( LPCTSTR szField );
	//	Gets a field by number
	CDBField&	operator()( int nField );


	//	Get values by field names. Do conversion as appropriate.

	bool			GetBool( LPCTSTR szName );
	unsigned char	GetChar( LPCTSTR szName );
	short			GetShort( LPCTSTR szName );
	int				GetInt( LPCTSTR szName );
	long			GetLong( LPCTSTR szName );
	float			GetFloat( LPCTSTR szName );
	double			GetDouble( LPCTSTR szName );
	COleDateTime	GetDate( LPCTSTR szName );
	CString			GetString( LPCTSTR szName );
	CLongBinary*	GetBinary( LPCTSTR szName );


	//	Get values by field number. Do conversion as appropriate.

	bool			GetBool( int nCol );
	unsigned char	GetChar( int nCol );
	short			GetShort( int nCol );
	int				GetInt( int nCol );
	long			GetLong( int nCol );
	float			GetFloat( int nCol );
	double			GetDouble( int nCol );
	COleDateTime	GetDate( int nCol );
	CString			GetString( int nCol );
	CLongBinary*	GetBinary( int nCol );


private:
	CDBField*			m_fields;			//	Storage for fields
	int					m_AllocatedFields;	//	Used to make smart storage reallocation
	CMapStringToPtr		m_mapNameIdx;		//	Map field names to their ID
	bool				m_bNotLoadedFieldsMap;	//	Is field names map still not loaded

	void	LoadFieldNamesMap();

	//	Clear the internal data structures
	void	Clear();
	
	//	RFX support
	virtual	void	DoFieldExchange( CFieldExchange* pFX );

	//	Allocate data buffer and set the field type
	void		AllocDataBuffer( CDBVariant& varValue, CODBCFieldInfo& fi );
	short		GetCFieldType( short nSQLType );
};
/////////////////////////////////////////////////////////////////////////////



/////////////////////////////////////////////////////////////////////////////
//
//	CODBCRecordset class inline methods
//
/////////////////////////////////////////////////////////////////////////////

inline
//	Gets a field by name
CDBField&	CODBCRecordset::Field( LPCTSTR szName ) {
	return	Field( GetFieldID( szName ) );
}

inline
//	Gets a field by number
CDBField&	CODBCRecordset::Field( int nField ) {
	//	There is no allocated storage
	ASSERT( m_fields != NULL );
	//	The field ID is invalid
	ASSERT( nField >= 0 );
	ASSERT( nField < GetODBCFieldCount() );
	//	There is no data in the current recordset position
	ASSERT( IsOpen() );

	return	m_fields[ nField ];
}
////////////////////////////////////////////////////////////////
//	Get field methods

inline
CDBField&	CODBCRecordset::operator()( LPCTSTR szField ) {
	return	Field( szField );
}

inline
CDBField&	CODBCRecordset::operator()( int nField ) {
	return	Field( nField );
}
////////////////////////////////////////////////////////////////
//	Get by Column Name

inline
bool	CODBCRecordset::GetBool( LPCTSTR szName ) {
	return	Field( szName ).AsBool();
}

inline
unsigned char	CODBCRecordset::GetChar( LPCTSTR szName ) {
	return	Field( szName ).AsChar();
}

inline
short	CODBCRecordset::GetShort( LPCTSTR szName ) {
	return	Field( szName ).AsShort();
}

inline
int		CODBCRecordset::GetInt( LPCTSTR szName ) {
	return	Field( szName ).AsInt();
}

inline
long	CODBCRecordset::GetLong( LPCTSTR szName ) {
	return	Field( szName ).AsLong();
}

inline
float	CODBCRecordset::GetFloat( LPCTSTR szName ) {
	return	Field( szName ).AsFloat();
}

inline
double	CODBCRecordset:: GetDouble( LPCTSTR szName ) {
	return	Field( szName ).AsDouble();
}

inline
COleDateTime	CODBCRecordset::GetDate( LPCTSTR szName ) {
	return	Field( szName ).AsDate();
}

inline
CString	CODBCRecordset::GetString( LPCTSTR szName ) {
	return	Field( szName ).AsString();
}

inline
CLongBinary*	CODBCRecordset::GetBinary( LPCTSTR szName ) {
	return	Field( szName ).AsBinary();
}
////////////////////////////////////////////////////////////////
// Get by Column Number

inline
bool	CODBCRecordset::GetBool( int nCol ) {
	return	Field( nCol ).AsBool();
}

inline
unsigned char	CODBCRecordset::GetChar( int nCol ) {
	return	Field( nCol ).AsChar();
}

inline
short	CODBCRecordset::GetShort( int nCol ) {
	return	Field( nCol ).AsShort();
}

inline
int		CODBCRecordset::GetInt( int nCol ) {
	return	Field( nCol ).AsInt();
}

inline
long	CODBCRecordset::GetLong( int nCol ) {
	return	Field( nCol ).AsLong();
}

inline
float	CODBCRecordset::GetFloat( int nCol ) {
	return	Field( nCol ).AsFloat();
}

inline
double	CODBCRecordset:: GetDouble( int nCol ) {
	return	Field( nCol ).AsDouble();
}

inline
COleDateTime	CODBCRecordset::GetDate( int nCol ) {
	return	Field( nCol ).AsDate();
}

inline
CString	CODBCRecordset::GetString( int nCol ) {
	return	Field( nCol ).AsString();
}

inline
CLongBinary*	CODBCRecordset::GetBinary( int nCol ) {
	return	Field( nCol ).AsBinary();
}
////////////////////////////////////////////////////////////////

#endif		//		__ODBCRECORDSET_H__