static RC RollBackUpdate(SM_DbHandle &db, Event &event, RID &rid)
{
RC rc;
printf("QL: Undoing update.\n");
RM_FileHandle *pTableHandle;
if ((rc = db.FindTableHandle(event.tableName.c_str(), pTableHandle)))
return rc;
RM_Record record;
if ((rc = pTableHandle->GetRec(rid, record)))
return rc;
char *data;
if ((rc = record.GetData(data)))
return rc;
SM_Attribute *pAttr;
if ((rc = db.FindAttribute(event.tableName.c_str(), event.attrName.c_str(), pAttr)))
return rc;
// If indexed, remove the old entry.
IX_IndexHandle *pIndexHandle;
if (pAttr->hasIndex) {
if ((rc = db.FindIndexHandle(event.tableName.c_str(), event.attrName.c_str(), pIndexHandle)))
return rc;
if ((rc = pIndexHandle->DeleteEntry(data + pAttr->attrOffset, rid)))
return rc;
}
// Restore the record.
int recordSize = pTableHandle->header.recordSize;
memcpy(data, event.record, recordSize);
// Update the record.
if ((rc = pTableHandle->UpdateRec(record)))
return rc;
// If indexed, insert the new entry.
if (pAttr->hasIndex) {
if ((rc = pIndexHandle->InsertEntry(data + pAttr->attrOffset, rid)))
return rc;
}
return 0;
}
RC QL_Manager::Update()
{
RC rc;
vector<RM_Record> chosenRecords;
RM_FileHandle *pTableHandle;
if ((rc = db.FindTableHandle(rmp.relName, pTableHandle)))
return rc;
SM_Attribute *pAttr;
if ((rc = db.FindAttribute(rmp.relName, rmp.updAttr.attrName, pAttr)))
return rc;
if (rmp.rhsValue.type != pAttr->attrType && rmp.rhsValue.type != NOTYPE) {
fprintf(stderr, "QL: Update attributes with different type!\n");
return QL_ERR_INVALID_COMMAND;
}
if (rmp.rhsValue.type == NOTYPE && pAttr->notNull) {
fprintf(stderr, "QL: Update not-null attribute with NULL!\n");
return QL_ERR_INVALID_COMMAND;
}
if ((rc = FindRecords(rmp.relName, chosenRecords)))
return rc;
vector<RM_Record>::iterator pRecord;
int recordSize = pTableHandle->header.recordSize;
for (pRecord = chosenRecords.begin(); pRecord != chosenRecords.end(); pRecord++) {
RID rid;
if ((rc = pRecord->GetRid(rid)))
return rc;
char *data;
if ((rc = pRecord->GetData(data)))
return rc;
int *pNullBitmap = (int *)(data + recordSize - sizeof(int));
// Check primary key uniqueness.
SM_Attribute *attr = pAttr;
if (attr->isPrimary && !attr->hasIndex) {
RM_FileScan scan;
if ((rc = scan.OpenScan(*pTableHandle, attr->attrType,
attr->attrLength, attr->attrOffset,
attr->number,
EQ_OP, rmp.rhsValue.data)))
return rc;
RM_Record rec;
if (scan.GetNextRec(rec) != RM_ERR_EOF) {
fprintf(stderr, "QL: Primary key conflicts!\n");
scan.CloseScan();
return QL_PRIMARY_KEY;
}
if ((rc = scan.CloseScan()))
return rc;
}
// Check foreign key existence.
if (attr->isForeignKey) {
RM_FileHandle *pForeign;
if ((rc = db.FindTableHandle(attr->refTableName, pForeign)))
return rc;
SM_Attribute *foreignAttr;
if ((rc = db.FindAttribute(attr->refTableName, attr->refAttrName, foreignAttr)))
return rc;
if (foreignAttr->attrType != attr->attrType) {
fprintf(stderr, "QL: mismatch attribute type with foreign key.\n");
return rc;
}
RM_FileScan scan;
if ((rc = scan.OpenScan(*pForeign, foreignAttr->attrType,
foreignAttr->attrLength, foreignAttr->attrOffset,
foreignAttr->number,
EQ_OP, rmp.rhsValue.data)))
return rc;
RM_Record rec;
if (scan.GetNextRec(rec) != 0) {
fprintf(stderr, "QL: Foreign key does not exist!\n");
scan.CloseScan();
return QL_FOREIGN_KEY;
}
if ((rc = scan.CloseScan()))
return rc;
}
Event event;
event.type = UPDATE;
event.record = new char[recordSize];
event.tableName = rmp.relName;
event.attrName = rmp.updAttr.attrName;
memcpy(event.record, data, recordSize);
// If indexed, remove the old entry.
IX_IndexHandle *pIndexHandle;
if (pAttr->hasIndex) {
if ((rc = db.FindIndexHandle(rmp.relName, pAttr->attrName, pIndexHandle))) {
delete[] event.record;
return rc;
}
if ((rc = pIndexHandle->DeleteEntry(data + pAttr->attrOffset, rid))) {
delete[] event.record;
return rc;
}
}
map<RID, Event, RID_LessThan>::iterator pPrevEvent = transaction.find(rid);
if (pPrevEvent == transaction.end()) {
transaction.insert(pair<RID, Event>(rid, event));
} else {
delete[] event.record;
}
// Modify the record.
if (pAttr->attrType == INT || pAttr->attrType == FLOAT) {
memcpy(data + pAttr->attrOffset, rmp.rhsValue.data, pAttr->attrLength);
*pNullBitmap &= ~(1 << pAttr->number);
} else if (pAttr->attrType == NOTYPE) {
*pNullBitmap |= 1 << pAttr->number;
} else {
strncpy(data + pAttr->attrOffset, (const char *)rmp.rhsValue.data, pAttr->attrLength);
*pNullBitmap &= ~(1 << pAttr->number);
}
// Update the record.
if ((rc = pTableHandle->UpdateRec(*pRecord))) {
delete[] event.record;
return rc;
}
// If indexed, insert the new entry.
if (pAttr->hasIndex) {
if ((rc = pIndexHandle->InsertEntry(data + pAttr->attrOffset, rid))) {
delete[] event.record;
return rc;
}
}
}
return 0;
}