Patent ID: 7076490

Claim:
A method of deleting a class instance using an object-relational database management system (ORDBMS), the method comprising: (a) when a query to delete a class instance is input from a database access application program, obtaining a first mutual exclusive lock for a class of the instance to be deleted and a second mutual exclusive lock for a child class of the class; (b) checking a relationship between the class and the child class, wherein the relationship comprises a vertical relationship where at least one child class inherits from the class to be deleted and a horizontal relationship where the child class has a 1:1, or 1:N relationship to object identifiers stored in the class to be deleted; (c) deleting a reverse pointer indicating the instance to be deleted if it is determined in step (b) that the relationship is a horizontal relationship of 1:1; (d) deleting the instance from the reverse pointer indicating the instance if it is determined in step (b) that the relationship is a horizontal relationship of 1:N; and (e) deleting the instance of the class after steps (c) and (d) are properly performed.