public async Task <bool> MoveNext(CancellationToken cancellationToken)
{
try
{
if (_dataReader == null)
{
await _relationalQueryContext.Connection.OpenAsync(cancellationToken);
try
{
var selectExpression = new ParameterValueBasedSelectExpressionOptimizer(
_sqlExpressionFactory,
_parameterNameGeneratorFactory)
.Optimize(_selectExpression, _relationalQueryContext.ParameterValues);
var relationalCommand = _querySqlGeneratorFactory.Create().GetCommand(selectExpression);
_dataReader
= await relationalCommand.ExecuteReaderAsync(
_relationalQueryContext.Connection,
_relationalQueryContext.ParameterValues,
_relationalQueryContext.CommandLogger,
cancellationToken);
_resultCoordinator = new ResultCoordinator();
}
catch (Exception)
{
// If failure happens creating the data reader, then it won't be available to
// handle closing the connection, so do it explicitly here to preserve ref counting.
_relationalQueryContext.Connection.Close();
throw;
}
}
var hasNext = _resultCoordinator.HasNext ?? await _dataReader.ReadAsync(cancellationToken);
_resultCoordinator.HasNext = null;
Current
= hasNext
? await _shaper(_relationalQueryContext, _dataReader.DbDataReader, _resultCoordinator)
: default;
return(hasNext);
}
catch (Exception exception)
{
_logger.QueryIterationFailed(_contextType, exception);
throw;
}
}
public bool MoveNext()
{
try
{
if (_dataReader == null)
{
_relationalQueryContext.Connection.Open();
try
{
var projection = _selectExpression.Projection.ToList();
var selectExpression = new ParameterValueBasedSelectExpressionOptimizer(
_sqlExpressionFactory,
_parameterNameGeneratorFactory)
.Optimize(_selectExpression, _relationalQueryContext.ParameterValues);
var relationalCommand = _querySqlGeneratorFactory.Create().GetCommand(selectExpression);
_dataReader
= relationalCommand.ExecuteReader(
_relationalQueryContext.Connection,
_relationalQueryContext.ParameterValues,
_relationalQueryContext.CommandLogger);
var readerColumns = Enumerable.Range(0, _dataReader.DbDataReader.FieldCount)
.Select(
i => new
{
Name = _dataReader.DbDataReader.GetName(i),
Ordinal = i
}).ToList();
_indexMap = new int[projection.Count];
for (var i = 0; i < projection.Count; i++)
{
if (projection[i].Expression is ColumnExpression columnExpression)
{
var columnName = columnExpression.Name;
if (columnName != null)
{
var readerColumn
= readerColumns.SingleOrDefault(
c =>
string.Equals(columnName, c.Name, StringComparison.OrdinalIgnoreCase));
if (readerColumn == null)
{
throw new InvalidOperationException(RelationalStrings.FromSqlMissingColumn(columnName));
}
_indexMap[i] = readerColumn.Ordinal;
}
}
}
}
catch (Exception)
{
// If failure happens creating the data reader, then it won't be available to
// handle closing the connection, so do it explicitly here to preserve ref counting.
_relationalQueryContext.Connection.Close();
throw;
}
}
var hasNext = _dataReader.Read();
Current
= hasNext
? _shaper(_relationalQueryContext, _dataReader.DbDataReader, _indexMap)
: default;
return(hasNext);
}
catch (Exception exception)
{
_logger.QueryIterationFailed(_contextType, exception);
throw;
}
}
