Abstract: A partitioning scheme for co-locating records of a table with records they reference. In a distributed database system, records of one table or relation may be stored at different locations. In order to optimize database query processing the present invention partitions records of a table by reference. A record in a table may reference another record in the table or in another table. The present invention stores (or co-locates) the referencing record with the referenced record.

Abstract: An extensible digital library is comprised of a library server and an object server. The library server stores tables describing the digital library, wherein it uses a relational database server to manage the storage of the tables describing the digital library. The object server stores objects referenced by the tables describing the digital library. Two application programming interfaces (APIs) are provided. A first API is coupled to the library server and the object server and provides functions for accessing the stored tables and the stored objects via the library server and the object server. A second API is coupled to the first API and the relational database server and provides functions for accessing the stored tables via the relational database server.

Abstract: A multi-tiered indexing method is disclosed for a partitioned table in a parallel or distributed database system. A Local Index is created and maintained for each partition of the table and a Coarse Global Index is created and maintained. The Coarse Global Index identifies the indexed partition(s) by partition identifiers (PIDs) and associates the individual Index Key Values with their target partitions so that an access request with a highly partition-selective search predicate on the Index Key can be quickly and easily directed to the target partition(s) for processing. An index maintenance locking protocol is also disclosed which handles the insertion and deletion of index entries and assures the consistency between the Local Index entries and the Coarse Global Index entries during concurrent index accesses by different transactions.

Abstract: In a database system that stores database objects in partitioned mode using bins to represent storage locations at which individual records of an object are stored, after they have been partitioned into logical buckets, a cascaded round-robin mapping method assigns buckets to bins evenly, while minimizing the movement of buckets when new bins are added and while minimizing memory overhead requirements. The method includes entering a do loop for an index counter variable j=m to 0 by -1, wherein "m" is the number of times new bins have been added since the last database reorganization. A variable y is set equal to x modulo n.sub.j, wherein n.sub.j is the number of bins after the j.sup.th database expansion. If y.gtoreq.n.sub.j-1, y is established to be the bin identification. Buckets are moved to populate new bins based on modulo n+k, wherein k is the number of bins added in the current expansion.

Abstract: An efficient method for adding one or more new direct access storage devices (DASDs) to a redundant array of independent disks (RAID) array without disrupting ongoing operation of the array. In one embodiment, after contents of new DASDs are initialized off-line, the "parity" or "data" status of specific storage locations in the array is re-mapped, without any changes to the storage locations' contents. In a second embodiment, RAID arrays are efficiently expanded and parallelism is facilitated for original as well as new data by re-mapping parity and data tracks, changing the contents of a minimum number of tracks and maintaining the contents of others.