public void selectRecord(String tableName, ArrayList<Condition> conditions)
throws TableNotFoundException {
Table table = cm.getTable(tableName);
if (table == null) throw new TableNotFoundException(tableName);
Data selectResult = new Data();
for (int blockOffset = 0; blockOffset < table.blockNum; blockOffset++) {
BufferNode bn = bm.getBufferNode(table.name + ".table", blockOffset);
byte[] block = bn.data;
int recordNum = getRecordNum(block);
int recordIndex = 0;
int accessedRecordNum = 0;
while (accessedRecordNum < recordNum) {
int pos = getPositionFromIndex(table, recordIndex);
if (block[pos] == EMPTY) { // record is empty, skip
recordIndex++;
continue;
}
byte[] recordBytes = bn.getBytes(pos + 1, table.totalLength);
if (matchAllCond(table, recordBytes, conditions)) {
byte[] bytes = bn.getBytes(pos + 1, table.totalLength);
selectResult.add(new Row(bytesToString(table, bytes)));
}
recordIndex++;
accessedRecordNum++;
}
}
displaySelectResult(table, selectResult);
}
public int deleteRecord(String tableName, List<Condition> conditions)
throws TableNotFoundException, Exception {
Table table = cm.getTable(tableName);
if (table == null) throw new TableNotFoundException(tableName);
int count = 0;
for (int blockOffset = 0; blockOffset < table.blockNum; blockOffset++) {
BufferNode bn = bm.getBufferNode(table.name + ".table", blockOffset);
byte[] block = bn.data;
int recordNum = getRecordNum(block);
int recordIndex = 0;
int accessedRecordNum = 0;
int nextDeleted = getInsertIndex(block);
int prevDeleted = -1;
ArrayList<Index> allTableIndices = cm.getAllIndicesOfTable(tableName);
while (accessedRecordNum < recordNum) {
int pos = getPositionFromIndex(table, recordIndex);
if (block[pos] == EMPTY) { // record is empty, skip
recordIndex++;
continue;
}
byte[] recordBytes = bn.getBytes(pos + 1, table.totalLength);
if (matchAllCond(table, recordBytes, conditions)) {
block[pos] = EMPTY;
if (recordIndex < nextDeleted) {
setNextInsertIndex(block, table, prevDeleted, recordIndex);
setNextInsertIndex(block, table, recordIndex, nextDeleted);
prevDeleted = recordIndex;
} else {
int nextOfNext = getNextInsertIndex(block, table, nextDeleted);
setNextInsertIndex(block, table, nextDeleted, recordIndex);
setNextInsertIndex(block, table, recordIndex, nextOfNext);
nextDeleted = nextOfNext;
prevDeleted = recordIndex;
}
decRecordNum(block);
// there remains some space for insertion
if (table.nextInsertBlock > blockOffset) table.nextInsertBlock = blockOffset;
// Delete in index
for (Index idx : allTableIndices) {
byte[] key = Arrays.copyOfRange(recordBytes, idx.pos, idx.pos + idx.columnLength);
im.deleteKey(idx, key);
}
bn.isWritten = true;
count++;
}
recordIndex++;
accessedRecordNum++;
}
}
return count;
}
