update method

Future<int> update(
  1. {@required String table,
  2. @required Map<String, String> row,
  3. @required String where,
  4. bool verbose = false}
)

Update some datapoints in the database

Implementation

Future<int> update(
    {@required String table,
    @required Map<String, String> row,
    @required String where,
    bool verbose = false}) async {
  /// [table] is the table to use, [row] is a map of the data to update
  /// and [where] the sql where clause
  ///
  /// Returns a future with a count of the updated rows
  var updated = 0;
  await _mutex.synchronized(() async {
    if (!_isReady) {
      throw DatabaseNotReady();
    }
    final timer = Stopwatch()..start();
    try {
      var pairs = "";
      final n = row.length - 1;
      var i = 0;
      final datapoint = <String>[];
      final buf = StringBuffer();
      for (final el in row.keys) {
        buf..write("$pairs")..write("$el")..write("= ?");
        pairs = buf.toString();
        datapoint.add(row[el]);
        if (i < n) {
          pairs = ", ";
        }
        i++;
      }
      final q = 'UPDATE $table SET $pairs WHERE $where';
      await _db.transaction((txn) async {
        updated = await txn.rawUpdate(q, datapoint);
      }).catchError((dynamic e) => throw WriteQueryException(
          "Can not update data in table $table $e"));
      final qStr = "$q $datapoint";
      timer.stop();
      _changeFeedController.sink.add(DatabaseChangeEvent(
          type: DatabaseChange.update,
          value: updated,
          query: qStr,
          table: table,
          data: row,
          executionTime: timer.elapsedMicroseconds));
      if (verbose) {
        final msg = "$q $row in ${timer.elapsedMilliseconds} ms";
        print(msg);
      }
      return updated;
    } catch (e) {
      rethrow;
    }
  });
  return updated;
}