| 摘要 |
An information retrieval apparatus for processing a query for retrieval of information from a database has a mechanism for locating a number of features and feature fragments in an index database; an evaluating mechanism for identifying a number of sub-queries of a number of levels contained in the query and recursively evaluating the sub-queries using each of the located features and feature fragments; and a mechanism for collecting and storing a number of results of the recursive evaluation of the query and sub-queries pursuant to computing an overall result of the query. Such a system can eliminate the need of conventional retrieval systems for providing a new, separate, centralized replica within the data warehouse of the data stored in the diverse external databases. The invention can thus avoid the problems of replication of such data in conventional systems, in which the data may become stale or is subject to errors arising during replication for warehousing. Instead, the data warehouse can contain an index database, which stores entries providing data regarding the information stored in the external databases, such as information location specifiers for that data within those databases, relational information and statistics. The invention can also provide a robust, versatile indexing system.
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