Tackling Polytype Queries in Inconsistent Databases: Theory and Algorithm
نویسندگان
چکیده
منابع مشابه
Tackling Polytype Queries in Inconsistent Databases: Theory and Algorithm
To expand query types under a set of integrity constraints for obtaining consistent answers over inconsistent databases, a computational theory is proposed based on first-order logic. According to directed join graphs of queries and their join completeness, computational complexities of CQA are PTIME if query types are key-key, nonkey-key, incomplete key-key with acyclic join. This paper presen...
متن کاملInconsistent Databases
SCIENTIFIC FUNDAMENTALS A database can be seen as a model, i.e. as a simplified, abstract description, of an external reality. In the case of relational databases, one starts by choosing certain predicates of a prescribed arity. The schema of the database consists of this set of predicates, possibly attributes, which can be seen as names for the arguments of the predicates, together with an ind...
متن کاملQuery Answering in Inconsistent Databases
In this chapter, we summarize the research on querying inconsistent databases we have been conducting over the last five years. The formal framework we have used is based on two concepts: repair and consistent query answer. We describe different approaches to the issue of computing consistent query answers: query transformation, logic programming, inference in annotated logics, and specialized ...
متن کاملScalar aggregation in inconsistent databases
We consider here scalar aggregation queries in databases that may violate a given set of functional dependencies. We define consistent answers to such queries to be greatest lowest/least upper bounds on the value of the scalar function across all (minimal) repairs of the database. We show how to compute such answers. We provide a complete characterization of the computational complexity of this...
متن کاملQuerying Inconsistent Databases
Data integration aims to provide a uniform integrated access to multiple heterogeneous information sources designed independently and having strictly related contents. However, the integrated view, constructed by integrating the information provided by the different data sources by means of a specified integration strategy could potentially contain inconsistent data; that is, it can violate som...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Software
سال: 2012
ISSN: 1796-217X
DOI: 10.4304/jsw.7.8.1861-1866