Conceptual models are well-known tools to achieve a good design of information systems. Nevertheless, the understanding and use of all the constructs and constraints which are presented in such models are not an easy task and sometimes it is cause of loss of interest. In this chapter we have tried to study in depth and clarify the meaning of the features of conceptual models. The disagreements ...

Semantic optimization of database queries, i.e. the use of metadata (constraints) for query optimization, is well investigated and has led to signi cant performance gains. The algorithm semantically rewriting database queries presented in [2] is applicable to CEP queries with some adaptions. One of these adaptions concerns the treatment of views and the constraints for them. To reduce the numbe...

The point (0.5, 0.5, 0.5) ∈ P1, i.e. it satisfies the constraints above; however it is not in the convex hull of the matching vectors. The above example motivates the following family of additional constraints (introduced by Edmonds). Observe that for any matching M , the subgraph induced by M on any odd cardinality vertex subset U has at most (|U | − 1)/2 edges. Thus, without losing any of the...

We consider the problem of deciding the satisfiability of quantifier-free formulas in the theory of finite sets with cardinality constraints. Sets are a common high-level data structure used in programming; thus, such a theory is useful for modeling program constructs directly. More importantly, sets are a basic construct of mathematics and thus natural to use when formalizing the properties of...

Key and foreign key constraints are useful for XML 5] data in semantic speciication, query optimization and more importantly, for information preservation in data exchange. Several XML proposals, e.g., XML Schema 28] and XML Data 21], support key and foreign key speciications. These constraints, however, may not be nitely satissable in the XML context. More specifically , given a DTD D and a ni...

Linear constraints are the most common constraints occurring in combinatorial problems. For some problems which combine linear constraints with highly combinatorial constraints, the best solving method is translation to SAT. Translation of a single linear constraint to SAT is a well studied problem, particularly for cardinality and pseudoBoolean constraints. In this paper we describe how we can...

Despite the increasing demand for an effective XML document repository, many are still reluctant to store XML documents in their natural tree form. One main reason is the inadequacy of XML query languages to update the tree-form XML documents. Even though some of the languages have supported minimum update facilities, they do not concern on preserving the documents constraints. The results are ...

In this paper, we address the problem of changing the constraints of a mediated schema M to accommodate the constraints of a new export schema E0. We first show how to translate the constraints of E0 to the vocabulary of M, creating a set of constraints C0 in such a way that the schema mapping for E0 is correct. Then, we show how to compute the new version of the constraints of M to accommodate...

We study the computational complexity of reasoning with global constraints. We show that reasoning with such constraints is intractable in general. We then demonstrate how the same tools of computational complexity can be used in the design and analysis of specific global constraints. In particular, we illustrate how computational complexity can be used to determine when a lesser level of local...

We explore the criteria that contribute to the structural validity of modeling structures within the entityrelationship (ER) diagram. Our approach examines cardinality constraints in conjunction with the degree of the relationship to address constraint consistency, state compliance, and role uniqueness issues to derive a complete and comprehensive set of decision rules. Unlike typical other ana...