DATABASE INDEX KEY UPDATE METHOD AND PROGRAM

A method of database update processing for updating efficiently database index keys, when new database index keys are supplied to replace index keys already in the database, generates a delta data between the new and old data comprising insert and delete keys by delete processing from a coupled node tree holding the index keys in the old data using index keys of new data as delete keys, and generates new data by delete and insert processing from and into a coupled node tree holding index keys in old data as index keys using the delete keys and insert keys of the delta data.