On improving dependency implication algorithms
نویسندگان
چکیده
منابع مشابه
On Improving Dependency Implication Algorithms
Let 2 be a finite set of join dependencies (JDs), multivalued dependencies (MVDs) and functional dependencies (IDS). To test whether .% implies an MVD X -+ Y or an PD X -+ A, the procedure in [ 31 first generates the dependency basis DEP( X) of X with respect to 2. Then, X + Y if and only if Y is the union of some elements in DEP( X) , and X -+ A if and only if A E DEP( X), and there is an PD V...
متن کاملLogical Implication and Causal Dependency
Suppose that whenever event x occurs, a second event y must subsequently occur. We say that x “causes” y, or y is causally dependent on x. Deterministic causality abounds in software where execution of one routine can necessarily force execution of a subsequent subroutine. Discovery of such causal dependencies can be an important step to understanding the structure of undocumented, legacy code....
متن کاملImproving Dependency Pairs
The dependency pair approach [2, 12, 13] is one of the most powerful techniques for termination and innermost termination proofs of term rewrite systems (TRSs). For any TRS, it generates inequality constraints that have to be satisfied by weakly monotonic well-founded orders. We improve the dependency pair approach by considerably reducing the number of constraints produced for (innermost) term...
متن کاملA Simple Characterization of Database Dependency Implication
Functional dependencies [4] and multivalued dependencies [5,11] are important, widely-studied constraints on databases. A fundamental issue in database theory is the question of determining whether or not a given set of dependencies (in our case, functional and multivalued dependencies) logically implies another given dependency. We provide a simple and elegant set-theoretic characterization fo...
متن کاملAlgorithms for Minimal Dependency Set and Membership Based on XML Functional Dependency and Multi-Valued Dependency
As the XML functional dependency and multi-valued dependency impact on the normalization design of semi-structured data, definitions of XML functional dependency, XML multi-valued dependency, path dependency base and the minimal dependency set are given in this paper. Algorithms for minimal dependency set and membership with path expression based on the coexistence of XFD and XMVD are then prop...
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: Information Processing Letters
سال: 1997
ISSN: 0020-0190
DOI: 10.1016/s0020-0190(97)00158-0