// **********************************************************
// Delete a record from a page. Returns OK if everything went okay.
// Compacts remaining records but leaves a hole in the slot array.
// Use memmove() rather than memcpy() as space may overlap.
Status HFPage::deleteRecord(const RID& rid)
{
// fill in the body
//--- deal with errors ----
if(rid.pageNo < 0 || rid.slotNo < 0)
return MINIBASE_FIRST_ERROR(HEAPFILE, INVALID_SLOTNO);
//return FAIL;
if(rid.slotNo >= this->slotCnt)
return MINIBASE_FIRST_ERROR(HEAPFILE, INVALID_SLOTNO);
//return FAIL;
//--- deal with empty page case ---
if(empty())
return MINIBASE_FIRST_ERROR(HEAPFILE, NO_RECORDS);
//return FAIL;
//--- get record offset ---
int offset = getRecordOffset(rid);
//--- clean corresponding slot & get record length---
int len = cleanSlot(rid);
//--- deal with already deleted case ---
if(offset == INVALID_SLOT || len == EMPTY_SLOT)
return MINIBASE_FIRST_ERROR(HEAPFILE, ALREADY_DELETED);
//return FAIL;
//-- shrink slot directory ---
shrinkSlotDir();
//--- delete record & relocate behind records & slot dir ---
//--- & update usedPtr, freeSpace -----
deleteRec(offset, len);
return OK;
}
// **********************************************************
// Delete a record from a page. Returns OK if everything went okay.
// Compacts remaining records but leaves a hole in the slot array.
// Use memmove() rather than memcpy() as space may overlap.
Status HFPage::deleteRecord(const RID& rid)
{
// fill in the body
//---?? 注意未处理delete不存在record得特殊情况----
//--- get record offset ---
int offset = getRecordOffset(rid);
//--- clean corresponding slot & get record length---
int len = cleanSlot(rid);
//-- shrink slot directory ---
shrinkSlotDir();
//--- delete record & relocate behind records & slot dir ---
//--- & update usedPtr, freeSpace -----
deleteRec(offset, len);
return OK;
}
