display.cpp

用c语言实现的一个小型dbms

#include"Display.h"
#include"iostream"
#include <afx.h>
#include <stdlib.h>
#include<direct.h>

extern char CurLocation[256];                                   //<---存有当前正在使用的表的相对路径,
extern char CurRelationName[33];                                //<---存当前表的表名
extern char CurDB[33];

void ShowTable()
{
    CFileFind finder;

    int iRowN = 0;
    char loc[256];
	CString Dbn(CurDB);
    int iNameLen = 0,iTemp = 0;
	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';
	std::cout<<"| Tables in ";
    std::cout << (LPCTSTR) Dbn;
    int strNum = Dbn.GetLength();
	for(iTemp = 19 - iNameLen-strNum;iTemp != 0;iTemp--)
		 std::cout<<' ';
	std::cout <<"|"<<'\n';
	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';
	strcpy(loc,CurLocation);
	strcat(loc,"*.dbf");
    int bWorking = finder.FindFile(loc);

	while(bWorking)
	{
		 bWorking = finder.FindNextFile();
		 if (finder.IsDots())
			continue;
		 iRowN++;
         CString str = finder.GetFileTitle();
         iNameLen = str.GetLength(); 
		 std::cout <<"| "<< (LPCTSTR) str;
		 for(iTemp = 29 - iNameLen;iTemp != 0;iTemp--)
			 std::cout<<' ';
		std::cout <<"|"<<'\n';
	}
	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';
	std::cout<<"There are" <<iRowN<<" rows in the table!";
	finder.Close();

}



void ShowDB()
{

	CFileFind finder;
	int iRowN = 0;
    int iNameLen = 0,iTemp = 0;
	std::cout<<"These are the databases !\n";
    int bWorking = finder.FindFile("..\\Data\\*.*");
	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';//<---计32个字符
	std::cout<<"| Database                     |"<<'\n';
	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';//<---计32个字符
	while(bWorking)
	{
		
      bWorking = finder.FindNextFile();
	  if (finder.IsDots())
         continue;
	  
      if (finder.IsDirectory())
      {
		 iRowN++;
         CString str = finder.GetFileTitle();
		 iNameLen = str.GetLength(); 
		 std::cout <<"| "<< (LPCTSTR) str;
		 for(iTemp = 29 - iNameLen;iTemp != 0;iTemp--)
			 std::cout<<' ';
		std::cout <<"|"<<'\n';
	  }   	  
	}
   	std::cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"<<'\n';//<---计32个字符
	std::cout<<"There are" <<iRowN<<" rows in the database!";
	finder.Close();
}

 int CheckDB(char* pDb)
 {
  CFileFind finder;
  char loc[256];
  strcpy(loc,"..\\Data\\");
  strcat(loc,pDb);
  int  bWorking = finder.FindFile(loc);
  int iNameLen = 0,iTemp = 0;

  return bWorking;
 }

   int CheckTB(char* pTb)                   //<---检查tb是否存在
 {
  CFileFind finder;
  char loc[256];
  strcpy(loc,"..\\Data\\");
  strcat(loc,CurDB);
  strcat(loc,"\\");
  strcat(loc, pTb);                         //<---该目录下所有的文件
  strcat(loc , ".idx");                     //<---该目录下所有的文件
	
  int  bWorking = finder.FindFile(loc);
  int iNameLen = 0,iTemp = 0;

  return bWorking;

 }
 void DelDB(char* pDb)
 {
    char loc[256];
	char locfile[256];
	CFileFind finder;
	strcpy(locfile,pDb);                    //<---所要删除的目录的路径  
	strcpy(loc,pDb);                        //<---所要删除的目录的路径
    strcat(locfile , "\\*.*");              //<---该目录下所有的文件
	int bWorking = finder.FindFile(locfile);
	while(bWorking)
	{
      bWorking = finder.FindNextFile();
	  if (finder.IsDots())
         continue;
	  
      if (!finder.IsDirectory())
      {
		 CString str = finder.GetFilePath();
		 CFile::Remove( str );
		  }   	  
	}
	finder.Close();

    //删除空目录--->
    if( _rmdir( loc ) == 0 )
    	std::cout<<"Directory "<<loc<<" was successfully removed\n";
    else 
	 	std::cout<<"Can not remove database"<<loc<<"\n";

    ResetDBinfo();                          //<---删除数据库之后将全局路径重新设置
    
 }

 void ResetDBinfo()
{
	strcpy(CurLocation,"..\\data\\");
	strcpy(CurRelationName,"");
	strcpy(CurDB,"");
}

  void DelTB(char* pTb)
 {	char loc[256];
	char locfile[256];
	CFileFind finder;
  strcpy(locfile,pTb);                      //<---locfile为所要删除的table的目录
  strcpy(loc,locfile);                      //<---locfile为所要删除的table的目录

  strcat(locfile , ".idx");                 //<---该目录下所有的文件
	int bWorking = finder.FindFile(locfile);
	while(bWorking)
	{
	  bWorking = finder.FindNextFile();
	  if (finder.IsDots())
         continue;

	  if (!finder.IsDirectory())
      {
		 CString str = finder.GetFilePath();
		 CFile::Remove( str );
	  }   	  
	}
	finder.Close();   

  strcat(loc , ".dbf");                     //<---该目录下所有的文件
  bWorking = finder.FindFile(loc);
	while(bWorking)
	{
	  bWorking = finder.FindNextFile();
	  if (finder.IsDots())
         continue;

	  if (!finder.IsDirectory())
      {
		 CString str = finder.GetFilePath();
		 CFile::Remove( str );
      }   	  
	}
	finder.Close(); 

 }

 void CreateDB(char* pDb)
 {
	char loc[256];                          //所要创建的目录的路径
	CFileFind finder;
	strcpy(loc,"..\\Data\\");
    strcat(loc,pDb);
    //创建目录
    if( _mkdir( loc ) == 0 )
    	std::cout<<"database "<<pDb<<" was successfully created\n";
    else 
	 	std::cout<<"Can not create database "<<pDb<<"\n";
	finder.Close();
 }