DATABASE SYSTEM, AND DATABASE MANAGEMENT METHOD

摘要

A database system has an interface for a storage device, and a control device for accessing the storage device via the interface. The storage device stores: tables for managing a plurality of rows having a plurality of item values; and indices configured in a tree-structure from a plurality of nodes which make it possible to use one or more item values to identify rows. The control device identifies item value conditions included in the search conditions of a search query, and determines whether a node of an index corresponding to the item value conditions is inaccessible. In cases when the node is inaccessible, the control device identifies the range of item values managed by the inaccessible node, and searches the identified range for rows which satisfy the search conditions.