Compressed data structure for extracted changes to a database and method of generating the data structure

摘要

A method of identifying and storing data changes of a first compressed database compared with a previous compressed database and updating a second compressed database on a user device based on the stored data changes. Data changes are stored in a compressed data structure and data in the first, second, and previous compressed databases is stored in compressed form in one or more uniquely identified data pages. A data page of the first compressed database and the previous compressed database are decompressed and an entry from the first and previous compressed databases is read and compared. If the read entries differ, a type of action performed on the previous entry is identified and an entry in a delta file based on the read entry comparison is stored. The delta file is then compressed. The second compressed database is updated based on the delta file.