read<D extends Object> method Null safety

D? read<D extends Object>(
  1. Expression<D> expr

Reads a single column from an expr. The expression must have been added as a column, for instance via JoinedSelectStatement.addColumns.

To access the underlying columns directly, use rawData.


D? read<D extends Object>(Expression<D> expr) {
  if (_parsedExpressions.containsKey(expr)) {
    return _parsedExpressions[expr] as D?;

  throw ArgumentError(
      'Invalid call to read(): $expr. This result set does not have a column '
      'for that expression.');