The impact of the constant complement approach towards view updating

• view 20

http://dl.acm.org/citation.cfm?id=773159

view

a means to structure information with respect to specific user’s needs. frequently, users do not directly access stored database relations, instead, they access desired information in terms of views as part of an external schema.

read access through views is easy to handle, update requests through views are difficult in the sense that they have to be translated into appropriate updates on database relations.

… a novel characterization is established showing that constant complement translators exist precisely if users have a chance to undo all effects of their view updates using further view updates.

the question of whether a unique translation of a given view update exists is undecidable in general¹