G PHYSICS
G06 COMPUTING; CALCULATING OR COUNTING
G06F ELECTRIC DIGITAL DATA PROCESSING
G06F16/00 Information retrieval; Database structures therefor; File system structures therefor
G06F16/20 of structured data, e.g. relational data
G06F16/22 Indexing; Data structures therefor; Storage structures
G06F16/2228 Indexing structures