| 摘要 |
PURPOSE: A class instance update method is provided to update a class instance with a set of object identifiers for guarantying a consistency of a database in a case of updating instances of vertically interrelated classes. CONSTITUTION: The method comprises steps of receiving a query of an instance update request from a data access application program(401), analyzing the query and storing the query data(402), checking if the query is an update query(403), in a case of the update query in the step 403, calling a function of a "getLock()" for requesting a mutual exclusive lock to a class(404), checking if the mutual exclusive lock on the requested class is acquired(405), in a case that it is acquired in the step 405, searching the current class and lower classes for an instance satisfying conditions described in the query and repeating the next task while the instance satisfying conditions exists(406), updating all the instances satisfying the conditions and storing the update result(411), in a case that the mutual exclusive lock on the requested class is not acquired, retracting a transaction(413), and transmitting the successful update result or the transaction retracting to an application program(412). The task repetition step(406) includes steps of calling the function of the "getLock()" by designating an OID(Object Identifier), satisfying the conditions, as a parameter(407), checking a result(408), if the result is successful, increasing the number of updated instances by one(409), and if the result is not successful, retracting an update query(410).
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