glob_var.h

用c语言实现的一个小型dbms

#ifndef GLOB_VAR_H
#define GLOB_VAR_H

#include "Buffer.h"
#include <iostream>

using namespace std;

extern char CurLocation[256];
extern char CurRelationName[33];
extern char* ErrorMessage[];


enum MSG {CREATE,SELECT,INSERT,UPDATE,DELETE,DROP,QUIT,
          SHOWDB,SHOWTABLE,USE,HELP,UNORMAL,NEW,DEFAULT,DROPDB};

//I---int  C---char   F---float
enum  Column_Type {I,C,F};    
// >  >=  <  <=  =  !=  between…and…;
enum Operator_Type {B, BE, L, LE, E, NE,BETWEEN,ALL};


/////////////////////////////////////////////////////////////////////////////////////////////
//ptr是块指针，Offset精确定位到块中的具体位置
typedef struct TKey_Location* pKey_Location;
typedef struct TKey_Location
{
  _F_FileAddr ptr ; 
  int     offset; 
  bool operator==(TKey_Location key)
  {
    return (this->ptr == key.ptr && this->offset == key.offset);
  }
  bool operator!=(TKey_Location key)
  {
    if(this->ptr == key.ptr && this->offset == key.offset)
      return false;
    return true;
  }
}Key_Location;


/////////////////////////////////////////////////////////////////////////////////////////////
//支持int，char和float类型
union Column_Value
{
    int   		IntValue;	
    char* 		pCharValue;	 
    float 		FloatValue;	
};   		

/////////////////////////////////////////////////////////////////////////////////////////////
//catalog给index的关于选择范围的信息
//使用者：index
typedef struct TKey_Attr* pKey_Attr;
typedef struct TKey_Attr
{
   Column_Value		value;
   pKey_Attr		next;
   TKey_Attr(){next = NULL;}
}Key_Attr;

typedef  struct TCondtion_Info  
{										    
	Operator_Type	OperType;	
	pKey_Attr		min;		
	pKey_Attr		max;		
	TCondtion_Info(){
		min = NULL;
		max = NULL;
		OperType = B;
	}
}Condition_Info;

/////////////////////////////////////////////////////////////////////////////////////////////
//Catalog得出的关于选择需要的字段信息
//使用者：Record
typedef struct TSelect_Cell
{
	char			ColumnName[32];	
	Column_Type		ColType;	
	int				PriorLength;	
	int				ColLength;		
	TSelect_Cell*	next;		
	TSelect_Cell():PriorLength(0),ColLength(0),ColType(I) 
	{	
		this->next = NULL;
		strcpy(this->ColumnName,"");	
	}
}Select_Cell;

class Select_Rec_Info
{
public:
	Select_Cell*	head;
	int				ColumnNum;
    int             RecordLength;
	Select_Rec_Info():ColumnNum(0) {this->head=NULL;}
	~Select_Rec_Info(){};
};

/////////////////////////////////////////////////////////////////////////////////////////////
//Catalog将待插入记录填完整后形成的完整的记录信息
//使用者：Record
typedef  struct TCell_Info
{
	Column_Type	  	ColType;
	Column_Value	value;
	int 			PriorLength;	
	int				ColLength;	
	TCell_Info*		next;
	TCell_Info(){
		next = NULL;
		ColType = I;
		PriorLength = 0;
		ColLength = 0;
	}
}Cell_Info;
class Rec_Info
{
public:
	Cell_Info* 		head;
	int				    ColNum;
	int				    RecordLength;
  Rec_Info(){
		head = NULL;
		ColNum = 0;
	}
	~Rec_Info(){};
};


#endif  //GLOB_BAR_H