public override Transform GetTransformReader(Table table, bool previewMode = false)
{
var flatFile = (FlatFile)table;
var reader = new ReaderFlatFile(this, flatFile, previewMode);
return(reader);
}
public override async Task <object> ExecuteScalar(Table table, SelectQuery query, CancellationToken cancellationToken)
{
var timer = Stopwatch.StartNew();
var flatFile = (FlatFile)table;
using (var reader = new ReaderFlatFile(this, flatFile, true))
{
var openResult = await reader.Open(0, query, cancellationToken);
if (!openResult)
{
throw new ConnectionException($"Failed to run execute scalar on {table.Name}. The reader failed to open.");
}
var row = await reader.ReadAsync(cancellationToken);
if (row)
{
var value = reader[query.Columns[0].Column.Name];
return(value);
}
else
{
return(null);
}
}
}
