insert.c

linux 下用c++ 开发的一个小型数据库系统

#include "catalog.h"
#include "query.h"

/*
 * Inserts a record into the specified relation.
 *
 * Returns:
 * 	OK on success
 * 	an error code otherwise
 */

const Status QU_Insert(const string & relation, 
	const int attrCnt, 
	const attrInfo attrList[])
{
// part 5    
  InsertFileScan	*ifs ;
  RID		 	rid ;
  Record		rec ;
  char			*mydata ;
  int			len = 0 ;
  Status		status ;
  RelDesc		rds ;
  AttrDesc		ads ;
  int			i, n, myattrCnt ;
  string		astr ;
  int			intval ;
  float			flval ;
  AttrDesc		*attrs ;
  int			chklast ;

  status = relCat->getInfo( relation.c_str(), rds) ;
  if (status != OK) return status ;
  
  astr.append("begin") ;
  for( i = 0; i < attrCnt; i++){
    astr.erase(1) ;
    n = strlen(attrList[i].attrName) ;
    astr.replace( 0, n, attrList[i].attrName) ;
    if((status = attrCat->getInfo( relation, astr, ads)) != OK) return status ;
  }

  attrCat->getRelInfo( relation, myattrCnt, attrs) ;
  
  len = 0 ;
  for ( i = 0; i < myattrCnt; i++)
    len = len + attrs[i].attrLen ; 

  astr.append("insert") ;
  mydata = new char[len] ; 
  for (i = 0; i < len; i++) mydata[i] = 0;
 
  for ( i = 0; i < myattrCnt; i++){
    for (int t = 0; t < attrCnt; t++){
      if (strcmp(attrs[i].attrName,attrList[t].attrName) == 0){
      //  astr.erase(1) ;
      //  n = strlen(attrList[i].attrName) ;
      //  astr.replace( 0, n, attrList[i].attrName) ;
      //   attrCat->getInfo( relation, astr, ads) ;
        if ((Datatype)attrs[i].attrType == INTEGER){
          intval = atoi((char *)attrList[t].attrValue) ;
          memcpy( mydata + attrs[i].attrOffset, &intval, attrs[i].attrLen) ;
          break ;
        }
        if ((Datatype)attrs[i].attrType == FLOAT){
          flval = (float)atof((char *)attrList[t].attrValue) ;
          memcpy( mydata + attrs[i].attrOffset, &flval, attrs[i].attrLen) ;
          break ;
        }
        memcpy( mydata + attrs[i].attrOffset,attrList[t].attrValue, attrs[i].attrLen) ;
        break ;
      }
    }
  }


  rec.data = mydata ;
  rec.length = len ;
  ifs = new InsertFileScan( relation, status) ;
  if (status != OK){
    delete [] mydata ;
    return status ;
  }
  
  if((status = ifs->insertRecord( rec, rid)) != OK){
    delete [] mydata ;
    delete ifs ;
    return status ;
  }
  
  printf("\n  Table (%s)  1 Record Insert Success! \n", relation.c_str()) ;
  
  delete [] mydata ;
  delete ifs ;  
  return OK;
}