Method of recursively deriving and storing data in, and retrieving recursively-derived data from, a computer database system

摘要

A structure and method of arranging recursively derived data items in a database. A set of hierarchical iteration levels, one for each iteration of the recursive relation from which the data items are derived, is provided and all data items derived during a given iteration are associated with the corresponding iteration level. Also provided is an index structure including an index set of non-leaf nodes, a sequence set of leaf nodes, and an iteration level index. The leaf nodes include a record of the iteration level of each data item. The data are globally linked according to iteration level or are clustered on pages which are linked according to iteration level. Highly efficient scan and search are implemented by utilizing the iteration level index and the record of iteration level in the leaf nodes to direct the scanning and searching to data generated during a single iteration. The least fixpoint of a set of mutually recursive relations is efficiently calculated by these methods.