create.C

#include "catalog.h"
#include <cstring>

const Status RelCatalog::createRel(const string & relation, 
				   const int attrCnt,
				   const attrInfo attrList[])
{
  Status status;
  RelDesc rd;
  AttrDesc ad;

  if (relation.empty() || attrCnt < 1)
    return BADCATPARM;

  if (relation.length() >= sizeof rd.relName)
    return NAMETOOLONG;

  // make sure the relation doesn't already exist

  status = getInfo(relation, rd);
  if (status == OK)
    return RELEXISTS;
  if (status != RELNOTFOUND)
    return status;

  // make sure there are no duplicate attribute names

  unsigned int tupleWidth = attrList[0].attrLen;

  if (attrCnt > 1) {
    for(int i = 1; i < attrCnt; i++) {
      tupleWidth += attrList[i].attrLen;
      for(int j = 0; j < i; j++)
	if (strcmp(attrList[i].attrName, attrList[j].attrName) == 0)
	  return DUPLATTR;
    }
  }
  
  if (tupleWidth > PAGESIZE)            // should be more strict
    return ATTRTOOLONG;

  cout << "Creating relation " << relation << endl;

  // insert information about relation

  strcpy(rd.relName, relation.c_str());
  rd.attrCnt = attrCnt;
  if ((status = addInfo(rd)) != OK)
    return status;

  // insert information about attributes

  strcpy(ad.relName, relation.c_str());
  int offset = 0;
  for(int i = 0; i < attrCnt; i++) {
    if (strlen(attrList[i].attrName) >= sizeof ad.attrName)
      return NAMETOOLONG;
    strcpy(ad.attrName, attrList[i].attrName);
    ad.attrOffset = offset;
    ad.attrType = attrList[i].attrType;
    ad.attrLen = attrList[i].attrLen;
    if ((status = attrCat->addInfo(ad)) != OK)
    {
	cout << "got error return"  << status << endl;
      return status;
    }
    offset += ad.attrLen;
  }

  // now create the actual heapfile to hold the relation
  status = createHeapFile (relation);
  if (status != OK) return status;
  return OK;
}