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;
}
public void insertRecord(String tableName, List<String> row)
throws TableNotFoundException, UniqueKeyException, Exception {
Table table = cm.getTable(tableName);
if (table == null) throw new TableNotFoundException(tableName);
byte[] bytesToInsert = getInsertBytes(table, row);
// check uniqueness
ArrayList<Index> allTableIndices = cm.getAllIndicesOfTable(tableName);
for (Index idx : allTableIndices) {
byte[] key = Arrays.copyOfRange(bytesToInsert, idx.pos, idx.pos + idx.columnLength);
if (im.searchEqual(idx, key) != null) throw new UniqueKeyException(idx.indexName);
}
// Use free list for insertion and deletion
int recordSize = table.totalLength + POINTER_SIZE;
while (true) {
// BufferNode bn = bm.getIfIsInBuffer(table.name + ".table", table.nextInsertBlock);
BufferNode bn = bm.getBufferNode(table.name + ".table", table.nextInsertBlock);
byte[] block = bn.data;
int insertIndex = getInsertIndex(block);
int pos = getPositionFromIndex(table, insertIndex);
// No free space, get a new block
if (pos + recordSize > BufferManager.BLOCK_SIZE) {
table.nextInsertBlock++;
if (table.nextInsertBlock >= table.blockNum) bm.addBlockInFile(table);
continue;
}
// Write to buffer
block[pos] = NOT_EMPTY;
System.arraycopy(bytesToInsert, 0, block, pos + 1, table.totalLength);
// Modify available insert index value and increase record number
int nextIndex = getNextInsertIndex(block, table, insertIndex);
setInsertIndex(block, nextIndex);
incRecordNum(block);
// Update index
for (Attribute attr : table.attributes) {
if (!attr.index.equals("")) { // has index
Index idx = cm.getIndex(attr.index);
byte[] key = Arrays.copyOfRange(bytesToInsert, idx.pos, idx.pos + idx.columnLength);
im.insertKey(idx, key, table.nextInsertBlock, pos);
}
}
bn.isWritten = true;
return;
}
}