delete method

Future<void> delete(Pointer<MDB_txn> txn, String key, { String? dbName, LMDBFlagSet? flags, })

Deletes a value from the database.

Parameters:

• txn - Active transaction
• key - Key to delete
• dbName - Optional named database. If not provided, the default database will be used.
• flags - Optional operation flags

Example:

final txn = await db.txnStart();
try {
  await db.delete(txn, 'key');
  await db.txnCommit(txn);
} catch (e) {
  await db.txnAbort(txn);
  rethrow;
}

Note: Does not throw if key doesn't exist

Implementation

Future<void> delete(
  Pointer<MDB_txn> txn,
  String key, {
  String? dbName,
  LMDBFlagSet? flags,
}) async {
  if (!isInitialized) throw StateError(_errDbNotInitialized);

  final dbi = await _getDatabase(txn, name: dbName, flags: flags);
  final keyPtr = key.toNativeUtf8();

  try {
    return _withAllocated<void, MDB_val>((keyVal) {
      keyVal.ref.mv_size = keyPtr.length;
      keyVal.ref.mv_data = keyPtr.cast();

      final result = _lib.mdb_del(
        txn,
        dbi,
        keyVal,
        nullptr,
      );

      if (result != 0 && result != MDB_NOTFOUND) {
        throw LMDBException('Failed to delete data', result);
      }
    }, calloc<MDB_val>());
  } finally {
    calloc.free(keyPtr);
  }
}