Simplified relational data base snapshot copying

Abstract

A relational data base management system permits users to specify copy operations without being burdened with specifying details of structure, copy refresh algorithm, and the like. The attributes a user must specify when requesting snapshot copies is reduced by defining data structures with attributes such that specifying the name of a table, whether a user data table or snapshot, specifies the copying scheme that will be used. Any ambiguity is resolved by interactively querying the user. When a user initially defines, or registers, a source table, the user specifies a set of predefined attributes, including table structure and completeness. When a user later requests a snapshot copy, the system automatically determines the nature of the copy operation to be performed by matching the table name with its registered attributes. This permits the system to automatically determine details such as the structure of the target table, the manner in which snapshot refresh will occur, and whether the target table can be created from a snapshot copy or if the original user table must be consulted. In this way, specifying copies in a relational data base system is simplified.