intepretor.cpp

实现一个精简型单用户SQL引擎(DBMS)MiniSQL

    {
     case I:
        tmin.IntValue = atoi(StrNow->str);
        NextStr();
        PassCommon("and");
        tmax.IntValue = atoi(StrNow->str);
        NextStr();
        pColtemp->SetColValint(optype,tmin.IntValue,tmax.IntValue);
       break;
     
     case F:
        tmin.FloatValue = atof(StrNow->str);
        NextStr();
        PassCommon("and");
        tmax.FloatValue = atof(StrNow->str);
        NextStr();
        pColtemp->SetColValfloat(optype,tmin.FloatValue,tmax.FloatValue);
       break;

     case C:
        tmin.pCharValue = FilterQuota(StrNow->str);
        NextStr();
        PassCommon("and");
        tmax.pCharValue = FilterQuota(StrNow->str);
        pColtemp->SetColValstr(optype,tmin.pCharValue,tmax.pCharValue);
       break;
    }
   }
else                                                  //<--- 非Between的操作类型,就可以直接设置
  {SetMin_Max(tmin,tmax,optype,coltype);
  pColtemp->SetColVal(optype,tmin,tmax);
  }                                                   //<--- 善后工作
PassCommon(")");
if(CompStrEver(StrNow->str,","))
  NextStr();
else
  if(CompStrEver(StrNow->str,")"))
    *NotEnd = 0;
}


EOPE_TYPE Ch_csVstrBlk::GetOptype()
{
/***************************************************************** 
** 功能描述:得到一个列的操作类型
 enum Operator_Type {B, BE, L, LE, E, NE,BETWEEN};
****************************************************************/ 
VSTR_BLK_PTR StrTemp = StrNow;
EOPE_TYPE ret;
if(CompStrEver(StrNow->str,"between"))
  ret = BETWEEN;
else
  if(CompStrEver(StrNow->str,"="))
	 {
	  NextStr();
	  ret = E;}
    else
      if(CompStrEver(StrNow->str,"!"))
       {NextStr();
        PassCommon("=");
        ret = NE;
       }
        else
          if(CompStrEver(StrNow->str,">"))
           {NextStr();
              if(CompStrEver(StrNow->str,"="))
			  {NextStr();
			  ret = BE;}
              else 
                ret = B;
            }
          else
            if(CompStrEver(StrNow->str,"<"))
             {NextStr();
              if(CompStrEver(StrNow->str,"="))                  //<--- 但是<时还要判断后面有没有=
			  {
				 NextStr();
			     ret = LE;}
              else 
                ret = L;
              }
            else
              ThrowStrErr(GET_OP_ERR,iNumNowInVstr);
    return ret;

}

pCreate_Column Ch_csVstrBlk::GetColForCheck(char* str,pCreate_Column pHead)
{
/***************************************************************** 
** 已知check中的列名,在前面已经只好的pHead列表中寻找该列的各个相关信息
****************************************************************/ 
pCreate_Column pCol = pHead,pTemp;
bool bNotFind = 1;
for(;pCol != 0 && bNotFind; pCol = pCol->next)
  {bNotFind = !(CompStrEver(pCol->ColumnName,str));
	pTemp = pCol;
  }                                         //<--- 在列链表中搜索所要找的列名
NextStr();
if(bNotFind)
  ThrowStrErr(COLNAMEERR_IN_CHECK,iNumNowInVstr);//<--- check的列名实际上并不存在
return pTemp;
}

pCreate_Column Ch_csVstrBlk::GetColumnInfo(bool* NotEnd,bool& bPriKeyExist)
{
  char strColName[NAMEMAXLEN];
  bool bError = 0,isnulltemp = 0,ispritemp = 0,ColNotEnd = 1;
  VSTR_BLK_PTR StrTemp = 0;
  pCreate_Column csOneCol = 0;
  ECOL_TYPE coltypetemp;
  int iStrlen = 0;
  strcpy(strColName,StrNow->str);           //<--- 得到一列的列名信息
  NextStr();
  if(CompStrEver(StrNow->str,"char"))
    {                                       //<--- 针对字段类型是char
	 coltypetemp = C;
	 NextStr();
     PassCommon("(");
	 if(CompStrEver(StrNow->str,")"))
		iStrlen = 0;
     else
	 {iStrlen = atoi(StrNow->str);
	 NextStr();}                            //<--- 如将har(8)中的8取得
     PassCommon(")");
    }
  else
    if(CompStrEver(StrNow->str,"int"))
     {                                      //<--- 针对字段类型是int
      coltypetemp = I;
	  NextStr();
     }
    else
      if(CompStrEver(StrNow->str,"float"))
        {                                   //<--- 针对字段类型是float
         coltypetemp = F;
		 NextStr();
        }
      else
       bError = 1;
  if(bError == 1)
    ThrowStrErr(COLUMNTYPE,iNumNowInVstr);

  do
  {
   if(CompStrEver(StrNow->str,"notnull"))   //<--- 有关一个列的定义之后如带有notnull或primary则记录下信息
    {isnulltemp = 0;
      NextStr();}
   else
     if(CompStrEver(StrNow->str,"primary"))
    {ispritemp = 1;
     bPriKeyExist = 1;                      //<--- primary key exists
      NextStr();}
     else
       if(CompStrEver(StrNow->str,","))
    {
     ColNotEnd = 0;
     NextStr();
    }
       else
         if(CompStrEver(StrNow->str,")"))
          {ColNotEnd = 0;
           *NotEnd = 0;}
           else 
             ThrowStrErr(KEYWORD,iNumNowInVstr);
  }while(ColNotEnd);
  csOneCol = new Create_Column(strColName,coltypetemp,iStrlen,isnulltemp,ispritemp);

  return csOneCol;
}


void Ch_csVstrBlk::NextStr()
{ 
/***************************************************************** 
** 功能描述:    转到下一个StrNow(即StrNow = StrNow->Next)
****************************************************************/ 
  iNumNowInVstr++;
  StrNow = StrNow->next;
}


char* Ch_csVstrBlk::GetTBName()
{                                           //<--- 取得表名
  char* strTBName = new char[NAMEMAXLEN];
  strcpy(strTBName,StrNow->str);
  NextStr();
  return strTBName;
}


void Ch_csVstrBlk::PassCommon(char* pStrIn)
 /***************************************************************** 
对StrNow当前所指的字串是否和输入的字串一致,一致---
则iNumNowInVstr++,StrNow = StrNow->next;
不一致--- ThrowStrErr(COMMON,iNumNowInVstr);
COMMON--意为所处理的是一般的关键字解析
****************************************************************/ 
{
  if(CompStrEver(pStrIn,StrNow->str))
    NextStr();
  else
    ThrowStrErr(COMMON,iNumNowInVstr);
}

ECMD_TYPE Ch_csVstrBlk::ResolveCmd()
 /***************************************************************** 
** 功能描述:解析取得命令
//<---  enum MSG { CREATE, SELECT, INSERT, UPDATE, DELETE, DROP, QUIT} ;
****************************************************************/ 
{
  ECMD_TYPE ReturnValue = HELP;
  bool bError = 0;
if(CompStrEver(StrNow->str,"HELP"))
	{ReturnValue = HELP;}
else
    if(CompStrEver(StrNow->str,"QUIT"))
	    {ReturnValue = QUIT;}
    else
        if(CompStrEver(StrNow->str,"EXIT"))
	        {ReturnValue = QUIT;}
        else
            if(CompStrEver(StrNow->str,"DROPDB"))
                ReturnValue = DROPDB;
            else
                if(CompStrEver(StrNow->str,"SHOWDB"))
                	ReturnValue = SHOWDB;
                else
                    if(CompStrEver(StrNow->str,"USE"))
                        ReturnValue = USE;
                    else
                        if(CompStrEver(StrNow->str,"NEW"))
                            ReturnValue = NEW;
                         else
                            if(CompStrEver(StrNow->str,"DROP"))
                                ReturnValue = DROP;
                            else
                                {
                                if(CompStrEver(StrNow->str,"CREATE"))
                                    ReturnValue = CREATE;
                                  else
                                    if(CompStrEver(StrNow->str,"SELECT"))
                                      ReturnValue = SELECT;
                                    else
                                      if(CompStrEver(StrNow->str,"INSERT"))
                                        ReturnValue = INSERT;
                                      else
                                        if(CompStrEver(StrNow->str,"UPDATE"))
                                          ReturnValue = UPDATE;
                                        else
                                          if(CompStrEver(StrNow->str,"DELETE"))
                                            ReturnValue = DELETE;
                                          else
                                                if(CompStrEver(StrNow->str,"SHOWTABLE"))
                                                  ReturnValue = SHOWTABLE;
                                                else
                                                    bError = 1;}
 
   if(bError == 1)
    ThrowStrErr(RESOLVE,iNumNowInVstr);
  else
    NextStr();                              //<--- 第一个有意字串不出错,则iNumNowInVstr+1
  return ReturnValue;
}

 void Ch_csVstrBlk::ThrowStrErr(int type,int iNum)
{                                           //<--- 负责构造一个错误类并将它抛出来,由主函数来处理
  ErrInfo eiTemp;
  int iLine = 0;
  int i = 0;
  char* str = new char[NAMEMAXLEN];
  VSTR_BLK_PTR StrTemp = StrHead;
  for(;iNum > iLineNum[iLine][1];iLine++)
	  ;
   i = iNum;                               //<--- 查找出错在那一行
  for(; i != 0;i--)
	  StrTemp = StrTemp->next;             //<--- 查找出错在哪个有意字串
  eiTemp.iErrType = type;
  eiTemp.iLineNo = iLine;
  strcpy(str,StrTemp->str);
  eiTemp.pErrStr = str;
  throw(eiTemp);
}

//<--- 设置好列中的Min&Max约束
void Ch_csVstrBlk::SetMin_Max(COLVAL temp,COLVAL& min,COLVAL& max,EOPE_TYPE optype,ECOL_TYPE coltype)
 {
	 switch(optype)
  {
  case E:
  case NE:
    switch(coltype)
    {case I:
        min = temp;
        max = min;
        break;
      case F:
		min = temp;
        max = min;
        break;
      case C:
        min = temp;
        max = min;
		break;
    }

  case LE:
  case L:
    switch(coltype)
    {case I:
        max = temp;
        break;
      case F:
        max = temp;
        
        break;
      case C:
        max.pCharValue = FilterQuota(temp.pCharValue);
        
        break;
    } 

  case B:
  case BE:
    switch(coltype)
    {case I:
        min = temp;
        
        break;
      case F:
        min = temp;
        
        break;
      case C:
        min.pCharValue = FilterQuota(temp.pCharValue);
        
        break;
        }
    
  }
 }

 void Ch_csVstrBlk::SetMin_Max(COLVAL& min,COLVAL& max,EOPE_TYPE optype,ECOL_TYPE coltype,bool next)
{
/******************************************************************* 
  功能描述:根据optype给min和max赋值
  当前StrNow必须处在处理的有意字串上
  enum Operator_Type {B, BE, L, LE, E, NE,BETWEEN};
****************************************************************/ 
switch(optype)
  {
  case E:
  case NE:
    switch(coltype)
    {case I:
        min.IntValue = atoi(StrNow->str);
        max.IntValue = min.IntValue;
        break;
      case F:
        min.FloatValue = atof(StrNow->str);
        max.FloatValue = min.FloatValue;
        break;
      case C:
        min.pCharValue = FilterQuota(StrNow->str);
        max.pCharValue = min.pCharValue;
        break;
    }

  case LE:
  case L:
    switch(coltype)
    {case I:
        max.IntValue = atoi(StrNow->str);
        break;
      case F:
        max.FloatValue = atof(StrNow->str);
        
        break;
      case C:
        max.pCharValue = FilterQuota(StrNow->str);
        
        break;
    }
    
  case B:
  case BE:
    switch(coltype)
    {case I:
        min.IntValue = atoi(StrNow->str);
        
        break;
      case F:
        min.FloatValue = atof(StrNow->str);
        
        break;
      case C:
        min.pCharValue = FilterQuota(StrNow->str);
        
        break;
        }
    
  }
	if(next)
		NextStr();

}
 /***********************结构体TB_Create_Info***********************/
 TB_Create_Info::TB_Create_Info(int i,pCreate_Column p,char* str):TotalColumn(i),head(p)
 {
    strcpy(TableName,str);
 }

 /***********************结构体Create_Column***********************/
Create_Column::Create_Column(char* str,ECOL_TYPE coltype,int strlen,bool is_null,bool ispri):
    ColType(coltype),length(strlen),IsNull(is_null),isprimary(ispri),next(0)
{
  strcpy(ColumnName,str);
  switch(coltype)
  {case C ://<--- 即该列为字符
    min.pCharValue = new char[2];
    strcpy(min.pCharValue,"z");
    max.pCharValue = new char[2];
    strcpy(max.pCharValue,"a");
   break;
   case F ://<--- 即该列为浮点数
    min.FloatValue = 1.0;
    max.FloatValue = 0;
   break;
   case I ://<--- 即该列为整数
     min.IntValue = 1;
     max.IntValue = -1;
   break;
   default :
   break;
  }
}

void Create_Column::SetColVal(EOPE_TYPE optype,COLVAL &tMin ,COLVAL &tMax)
{
  OperType = optype;
  min = tMin;
  max = tMax;
}

void Create_Column::SetColValstr(EOPE_TYPE optype,char* chMin = 0,char* chMax = 0)
{
/***************************************************************** 
将Create_Column()里未根据实际初始的min.pCharValue,max.pCharValue初始一下,并设定好长度
****************************************************************/ 
  int iStrLen = length;
  OperType = optype;
  if(chMin != 0)                            //<--- 如果min.pCharValue和max.pCharValue有范围限制
  {delete min.pCharValue;
  delete max.pCharValue;
  if(length == 0)
	  iStrLen = NAMEMAXLEN;
  min.pCharValue = new char[iStrLen];
  max.pCharValue = new char[iStrLen];
  strcpy(min.pCharValue,chMin);
  strcpy(max.pCharValue,chMax);
  }
}
void Create_Column::SetColValint(EOPE_TYPE optype,int iMin,int iMax)
{
/***************************************************************** 
将Create_Column()里未根据实际初始的min.IntValue,max.IntValue初始一下
****************************************************************/ 
  min.IntValue = iMin;
  max.IntValue = iMax;
  OperType = optype;