| Tradition Global Query of autonomous databases faces a few difficult issues including especially the hard problem of integrating and maintaining massively distributed and heterogeneous data models. In the traditional regime, databases are considered passive objects of the search process that respond to users' on-demand queries. The databases are typically configured as a component of a strict regime, in many cases subservient to a single authority, which rigorously defines and maintains the global database query infrastructure. Essentially, this regime hinders global database query in virtual enterprises, such as supply-chain management, where authority is distributed. The required integration of schemas is impractical in these virtual enterprises; instead what describes the nature of global query here is a new model of collaboration: databases offer their information on demand and put the information under their direct control. In the new model, they are equal participants as the users. Instead of being passive objects of global query, databases are regarded as proactive information providers that seek users searching for information they contain.; A high-level concept is proposed where information owners and seekers collaborate in an economic market to exchange information and facilitate each others' enterprises. The economic paradigm allows participants to collaborate voluntarily in an information exchange, to choose with whom to trade, and to also define the terms of the transaction. Accordingly, databases denoted as similarly as data publishers and subscribers publish the resources to be shared, and in contrast to traditional global query solutions, seek subscribers that are looking for information that they contain. The research however, ignores the pricing mechanism and addresses the problem of matching the attributes and constraints/conditions of publications with subscriptions.; The research develops a new information matching method for the Two-Stage Collaboration Model, consisting of an extended Metadata Query Language, a Query Database that is structured with the semantics of the query language, and a Matching Engine, which is part of a Blackboard that performs the assignment of databases (views) to queries on an on-demand basis. The new method is based on, and integrated with, the previous Metadatabase Model for Global Query. |
