METHOD AND APPARATUS FOR COMPRESSING AND DECOMPRESSING DIGITAL DATA BY ELECTRONIC MEANS USING A CONTEXT GRAMMAR

摘要

A method for electronically compressing and decompressing digital data using a context grammar includes grammatically compressing first digital data by discovering multiply occurring sequences of non-further-factorizable terminal symbols in the first digital data and replacing the discovered multiply occurring sequences of non-further-factorizable terminal symbols with non-terminal symbols that can be further factorized. Digital data belonging to the non-terminal symbols is stored in a context grammar. Second digital data is compressed using the context grammar. The first digital data relates to a column of data stored in a database and the second digital data relates to entries in the column of data stored in the database.