FIELD: index structure of metadata.;SUBSTANCE: in accordance to the invention, structure of metadata index includes a list of multi-keys and position information for defining multi-keys, while information is determined, which corresponds to search condition fields, and multi-key, corresponding to position information, is searched for, after that, metadata fragment is extracted using the found multi-key.;EFFECT: increased index search speed.;2 cl, 15 dwg, 6 tbl
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