load.C

#include <unistd.h>
#include <fcntl.h>
#include "catalog.h"
#include "utility.h"


//
// Loads a file of (binary) tuples from a standard file into the relation.
// Any indices on the relation are updated appropriately.
//
// Returns:
// 	OK on success
// 	an error code otherwise
//

const Status UT_Load(const string & relation, const string & fileName)
{
  Status status;
  RelDesc rd;
  AttrDesc *attrs;
  int attrCnt;

  if (relation.empty() || fileName.empty() || relation == string(RELCATNAME)
      || relation == string(ATTRCATNAME))
    return BADCATPARM;

  // open Unix data file

  int fd;
  if ((fd = open(fileName.c_str(), O_RDONLY, 0)) < 0)
    return UNIXERR;

  // get relation data

  if ((status = relCat->getInfo(relation, rd)) != OK) return status;

  // get attribute data
  if ((status = attrCat->getRelInfo(rd.relName, attrCnt, attrs)) != OK)
    return status;

  // open data file

  InsertFileScan* iFile = new InsertFileScan(rd.relName, status);
  if (!iFile) return INSUFMEM;
  if (status != OK) return status;

  int records = 0;

  // compute width of tuple and open index files, if any
  int width = 0;
  int i;

  for(i = 0; i < attrCnt; i++) {
    width += attrs[i].attrLen;
  }

  // create a record for constructing the tuple

  char *record;
  if (!(record = new char [width])) return INSUFMEM;

  int nbytes;
  Record rec;

  while((nbytes = read(fd, record, width)) == width) {
    RID rid;
    rec.data = record;
    rec.length = width;
    if ((status = iFile->insertRecord(rec, rid)) != OK) return status;
    records++;
  }

  cout << "Number of records inserted: " << records << endl;

  // close heap file and data file

  delete iFile;
  if (close(fd) < 0) return UNIXERR;

  delete [] record;
  free(attrs);

  return OK;
}