public void Column(string columnName)
{
if (mapping.Columns.UserDefined.Count() > 0)
{
return;
}
var originalColumn = mapping.Columns.FirstOrDefault();
var column = originalColumn == null ? new ColumnMapping() : ColumnMapping.BaseOn(originalColumn);
column.Name = columnName;
mapping.ClearColumns();
mapping.AddColumn(column);
}