Dynamic addition and removal of attributes in BANG files
Nalini Hosur, Huizhu Lu, G. E. Hedrick · 1992
ABSI'RACT BANG (Balartced and Nested Grid) tiles providefast access and updates of largemultidimmaiasal databases maintaid cmaeccmdarysttxage.'llris research extrnds the applicability of the BANGfde structureby allowing bosh@llXmiC q ddition and dyrsOmiC rmmvd of titIibutSS.Two new techniques, %rectory MaMkatioss Technique(DMT)" and "Multiple BANG FileTechnique (MBIT)" have bem developed andm.mcd.DMT USCSa geoosatricd a~ruach to acconrrnCdata the changes in the rrumhcrof attributes while MBFT uses separate BANG fdcs.Both of these methods mc twill rspar the existing BANG fde data structure.'llta number of disk accesses for the DMT when appropriately normalized shows a Iirrear relationship with the fractkm of total records whose attributes were modified.'Ms method is superior to the traditional regmeraticn of the BANG ftle for attributemodiicatimrson less than 50% of the records in the data t-k MBFT shows significant improvement ovcz a single large BANG fife in the number of disk acccsseJ for range and panial queries.As the fraction of the total data se-archedbecomes smafler, the improvements korne mom dramaac.The absolute reduction m disk accesses is mhanced as the range increases, or the number ol attributes in the partial query decrease.This method is particolarIy usetid for those files with large numhem of attributesor, where the data is dkibutad over a cunbmatiorr of attributes.