| 摘要 |
Data base administrator (10) creates program communication blocks (11), and programmer (12) writes programs (13) using the program communication blocks (PCBs) to store data in bulk storage device (14). A user (15) not having data processing skills or experience is enabled by means of a utility to access data in bulk storage device (14) via the PCBs (11). The utility first reads the data base descriptions (DBDs) and PCB source statements and constructs a data directory, consolidating access paths into entry data bases which are displayed to the user (15) as a menu. The utility then evaluates all possible access paths that will satisfy a user query, weights them according to their efficiency, and selects the best.
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