//
// Remove the tuple corresponding to relName from relcat. It performs the following steps:
//
// start a filter scan on relcat to locate the rid of the desired tuple
// call deleteRecord() to remove the tuple
//
// Returns:
// OK on success
// error code otherwise
//
const Status RelCatalog::removeInfo(const string & relation)
{
Status status;
RID rid;
HeapFileScan* hfs;
if (relation.empty()) return BADCATPARM;
//create a new file scan
hfs=new HeapFileScan(RELCATNAME, status);
if (status!=OK)
return status;
const char * relation_name_ptr = relation.c_str();
// open startScan, use the predicate to find matching record
status=hfs->startScan(0, MAXNAME, STRING, relation_name_ptr, EQ);
if (status!=OK)
return status;
Record rec;
// scan through relation catalog
// assume there is no duplicate
while ((status = hfs->scanNext(rid)) != FILEEOF){
// get record
status = hfs->getRecord(rec);
if (status!=OK)
return status;
//delete current record
hfs->deleteRecord();
delete hfs;
return OK;
}
return RELNOTFOUND;
}
const Status RelCatalog::removeInfo(const string & relation)
{
Status status = OK;
RID rid;
HeapFileScan* hfs;
if (relation.empty()) return BADCATPARM;
while (status == OK)
{
hfs = new HeapFileScan(RELCATNAME, status);
// you have to start a filter scan on relcat to locate the rid of the desired tuple.
status = hfs->startScan(0, relation.length() + 1, STRING, relation.c_str(), EQ);
status = hfs->scanNext(rid);
// delete the record
status = hfs->deleteRecord();
break;
}
if (status == NORECORDS)
{
return OK;
}
else if (status == FILEEOF)
{
return RELNOTFOUND;
}
else {
return status;
}
}
const Status RelCatalog::removeInfo(const string & relation)
{
Status status;
RID rid;
HeapFileScan* hfs;
if (relation.empty()) return BADCATPARM;
hfs = new HeapFileScan(RELCATNAME,status);
if (status != OK) return status;
hfs->startScan(0,relation.length(),STRING,relation.c_str(),EQ);
if (status != OK) return status;
status=hfs->scanNext(rid);
if (status != OK) return status;
status = hfs->deleteRecord();
if (status != OK) return status;
hfs->endScan();
delete hfs;
return OK;
}
const Status AttrCatalog::removeInfo(const string & relation,
const string & attrName)
{
Status status;
Record rec;
RID rid;
AttrDesc record;
HeapFileScan* hfs;
if (relation.empty() || attrName.empty()) return BADCATPARM;
hfs = new HeapFileScan(ATTRCATNAME,status);
if (status != OK) return status;
hfs->startScan(0,sizeof(record.relName),STRING,relation.c_str(),EQ);
if (status != OK) return status;
while ((status=hfs->scanNext(rid)) != FILEEOF)
{
if (status != OK) return status;
status=hfs->getRecord(rec);
if (status != OK) return status;
if (strncmp((char*)rec.data + sizeof(record.relName),attrName.c_str(),sizeof(record.attrName))==0)
{
status = hfs->deleteRecord();
if (status != OK) return status;
break;
}
}
hfs->endScan();
delete hfs;
return OK;
}
const Status QU_Delete(const string & relation,
const string & attrName,
const Operator op,
const Datatype type,
const char *attrValue)
{
Status status;
HeapFileScan *hfs;
AttrDesc record;
RID rid;
int tempInt;
float tempFloat;
hfs = new HeapFileScan(relation, status);
//Get the AttrDesc from the attrCat table
if (attrValue != NULL){
status = attrCat->getInfo(relation, attrName, record);
if (status != OK) return status;
}
//check type and cast accordingly
if(type == INTEGER){
tempInt = atoi(attrValue);
attrValue = (char *) &tempInt;
} else if(type == FLOAT){
tempFloat = atof(attrValue);
attrValue = (char *) &tempFloat;
}
//Start HFS on the relation table
status = hfs->startScan(record.attrOffset, record.attrLen, type, attrValue, op);
if(status != OK) return status;
while((status = hfs->scanNext(rid)) != FILEEOF){
if(status != OK) return status;
//Delete record if found in relation table
status = hfs->deleteRecord();
if(status != OK) return status;
}
//If end of file then return attribute not found
if (status == FILEEOF){
status = OK;
}
delete hfs;
return status;
}
const Status QU_Delete(const string & relation,
const string & attrName,
const Operator op,
const Datatype type,
const char *attrValue)
{
Status status;
Status ScanStatus = OK;
RID rid;
AttrDesc *ad;
int attrCnt;
HeapFileScan *hfs = new HeapFileScan(relation,status);
if(status != OK) {delete(hfs); return status;}
status = attrCat->getRelInfo(relation, attrCnt, ad);
if(status != OK) {delete(hfs); return status;}
// Find out the attribute's size
int attrSize;
int attrOffset;
for(int i = 0; i < attrCnt; i++)
if(strcmp(ad[i].attrName,attrName.c_str()) == 0) {
attrSize = ad[i].attrLen;
attrOffset = ad[i].attrOffset;
}
// Start a scan (* DO WE NEED TO CAST ATTRVALUE??)
status = hfs->startScan(attrOffset,attrSize,type,attrValue,op);
if(status != OK) {delete(hfs); return status;}
// Find and delete all matching records
ScanStatus = hfs->scanNext(rid);
while(ScanStatus != FILEEOF){
status = hfs->deleteRecord();
if(status != OK) {delete(hfs); return status;}
ScanStatus = hfs->scanNext(rid);
if(ScanStatus == FILEEOF)
{delete(hfs);
return OK;
}
}
// Done
delete(hfs);
return ScanStatus;
}
const Status AttrCatalog::removeInfo(const string & relation,
const string & attrName)
{
Status status = OK;
Record rec;
RID rid;
AttrDesc record;
HeapFileScan* hfs;
if (relation.empty() || attrName.empty()) return BADCATPARM;
while (status == OK)
{
hfs = new HeapFileScan(ATTRCATNAME, status);
// you have to start a filter scan on relcat to locate the rid of the desired tuple.
status = hfs->startScan(0, relation.length() + 1, STRING, relation.c_str(), EQ);
while (hfs->scanNext(rid) != FILEEOF)
{
status = hfs->getRecord(rec);
memcpy(&record, rec.data, rec.length);
if (strcmp(record.attrName, attrName.c_str()) == 0)
{
// Then you can call deleteRecord() to remove it
status = hfs->deleteRecord();
// break instead?
return status;
}
}
break;
}
if (status == FILEEOF)
{
return status;
}
else if (status == NORECORDS)
{
return OK;
}
else {
return status;
}
}
//
// Removes the tuple from attrcat that corresponds to attribute attrName of relation.
//
// Returns:
// OK on success
// error code otherwise
//
const Status AttrCatalog::removeInfo(const string & relation,
const string & attrName)
{
Status status;
Record rec;
RID rid;
HeapFileScan* hfs;
if (relation.empty() || attrName.empty()) return BADCATPARM;
hfs = new HeapFileScan(ATTRCATNAME,status);
if(status != OK)
return status;
const char* rel_name_ptr = relation.c_str();
const char* attr_name_ptr = attrName.c_str();
status = hfs->startScan(0,MAXNAME,STRING,rel_name_ptr,EQ);
if(status != OK){
delete hfs;
return status;
}
//first search all the attribute correspond to the relation
while((status = hfs->scanNext(rid)) != FILEEOF){
status = hfs->getRecord(rec);
if(status != OK){
delete hfs;
return status;
}
//find the attribute
if(memcmp(attr_name_ptr,((AttrDesc *)rec.data)->attrName,attrName.length() ) == 0){
//attribute found and detele
hfs->deleteRecord();
delete hfs;
//decrease the relation attrCnt
return OK;
}
}
delete hfs;
return ATTRNOTFOUND;
}
