public IFilter GetFilter()
 {
     return((IFilter)DatabaseObjects.Single(o => o is IFilter));
 }
 public object GetDataObject()
 {
     return(DatabaseObjects.Single(o => o is ColumnInfo || o is TableInfo));
 }
 public AggregateConfiguration GetGraph()
 {
     return((AggregateConfiguration)DatabaseObjects.Single(o => o is AggregateConfiguration));
 }