relview.cpp

有计算机图形学、图像处理、dbms、sniffer、中游俄罗斯外挂、othello、遗传算法、舌苔分析等程序。

// RelView.cpp: implementation of the CRelView class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "Database.h"
#include "RelView.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CRelView::CRelView()
{

}
CRelView::CRelView(CString n,UINT id,WORD an,UINT FN,UINT rno1,UINT rno2)
:attr_num(an),DataFileNo(FN),RelNo1(rno1),RelNo2(rno2)
{
	wtag=1;
	rcd_len=0;//辅助
	
	if(n.GetLength()<=10)
	{
		name=n;
		name_length=n.GetLength()+1;
	}
	else
	{
		name=n.Left(10);
		name_length=10+1;
	}
	time=CMemory::GetTime();
	at=new CAttribute[attr_num+1];
	length=GetHeadLength();//易出错
}
void CRelView::AddAttribute(USHORT index,CAttribute &a)
{
	ASSERT(index>=1&&index<=attr_num);
	a.offset=rcd_len;
	at[index]=a;
    length+=(a.GetLength());

	if(a.type==CHAR_TYPE)
		rcd_len+= (a.length+1);
	else if(a.type==VARCHAR_TYPE)
		rcd_len+= (a.length+2);
	else 
		rcd_len+= a.length;
}
WORD CRelView::GetHeadLength()
{
	return (2*sizeof(BYTE)+2*sizeof(WORD)+sizeof(int)
		+4*sizeof(UINT)+name_length+sizeof(PDB));
}
/***********************************************************************
/*  BYTE		exist;
/*	WORD		length;
/*	BYTE		name_length;
/*	CString		name;
/*	UINT		RelNo1;//所属关系号
/*	UINT		RelNo2;
/*	int			time;//时间戳
/*	UINT		DataFileNo;
/*	PDB			db_addr;
/*	UINT		rcd_len;//辅助
/*	WORD		attr_num;
/************************************************************************
/*  CAttribute	*at;
以上写入文件*************************************************************/
void CRelView::WriteBack()
{
    WORD i;
    CString filename("");
	BYTE exist=1;
	UINT offset=UINT(db_addr&0xFFFFFFFF);
	UINT fileno=UINT(db_addr>>32);
	filename.Format("D:\\DB\\%d.vscm",fileno);
    CViewSchemaFile vscmf(LPCTSTR(filename),CFile::modeReadWrite);
    vscmf.Seek(offset,CFile::begin);
	
	vscmf.Write(&exist,sizeof(BYTE));
	vscmf.Write(&length,sizeof(WORD));
	vscmf.Write(&name_length,sizeof(BYTE));
	vscmf.Write(LPCTSTR(name),name_length);
	vscmf.Write(&RelNo1,sizeof(UINT));
	vscmf.Write(&RelNo2,sizeof(UINT));
	vscmf.Write(&time,sizeof(int));
	vscmf.Write(&DataFileNo,sizeof(UINT));
	vscmf.Write(&db_addr,sizeof(PDB));
	vscmf.Write(&rcd_len,sizeof(UINT));
	vscmf.Write(&attr_num,sizeof(WORD));
	
	//写CAttribute
    for(i=1;i<=attr_num;i++)
	{
		vscmf.Write(&at[i].name_length,sizeof(BYTE));
		vscmf.Write(LPCTSTR(at[i].name),at[i].name_length);
		vscmf.Write(&at[i].type,sizeof(BYTE));
		vscmf.Write(&at[i].idx,sizeof(BYTE));
		vscmf.Write(&at[i].unq,sizeof(BYTE));
		vscmf.Write(&at[i].rf_relationship,sizeof(UINT));
		vscmf.Write(&at[i].rf_Attribute,sizeof(WORD));///!!!!!!!!!!!!!!!!
		vscmf.Write(&at[i].length,sizeof(WORD));
		vscmf.Write(&at[i].IndexMainFile,sizeof(UINT));
		vscmf.Write(&at[i].offset,sizeof(UINT));
	}
}
CRelView::~CRelView()
{
    delete []at;
}