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Constraint Query Languages
, 1992
"... We investigate the relationship between programming with constraints and database query languages. We show that efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction ..."
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Cited by 378 (45 self)
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We investigate the relationship between programming with constraints and database query languages. We show that efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction of constraints over a small number of variables. We describe the basic Constraint Query Language design principles and illustrate them with four classes of constraints: real polynomial inequalities, dense linear order inequalities, equalities over an infinite domain, and boolean equalities. For the analysis, we use quantifier elimination techniques from logic and the concept of data complexity from database theory. This framework is applicable to managing spatial data and can be combined with existing multidimensional searching algorithms and data structures.
Temporal Deductive Databases
, 1992
"... We survey a number of approaches to the problem of finite representation of infinite temporal extensions. Two of them, Datalog 1S and Templog, are syntactical extensions of Datalog; the third is based on repetition and arithmetic constraints. We provide precise characterizations of the expressivenes ..."
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Cited by 68 (10 self)
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We survey a number of approaches to the problem of finite representation of infinite temporal extensions. Two of them, Datalog 1S and Templog, are syntactical extensions of Datalog; the third is based on repetition and arithmetic constraints. We provide precise characterizations of the expressiveness and the computational complexity of these languages. We also describe query evaluation methods.
Constraint Programming and Database Query Languages
 In Proc. 2nd Conference on Theoretical Aspects of Computer Software (TACS
, 1994
"... . The declarative programming paradigms used in constraint languages can lead to powerful extensions of Codd's relational data model. The development of constraint database query languages from logical database query languages has many similarities with the development of constraint logic progr ..."
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Cited by 60 (3 self)
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. The declarative programming paradigms used in constraint languages can lead to powerful extensions of Codd's relational data model. The development of constraint database query languages from logical database query languages has many similarities with the development of constraint logic programming from logic programming, but with the additional requirements of data efficient, setatatime, and bottomup evaluation. In this overview of constraint query languages (CQLs) we first present the framework of [41]. The principal idea is that: "the ktuple (or record) data type can be generalized by a conjunction of quantifierfree constraints over k variables". The generalization must preserve various language properties of the relational data model, e.g., the calculus/algebra equivalence, and have time complexity polynomial in the size of the data. We next present an algebra for dense order constraints that is simpler to evaluate than the calculus described in [41], and we sharpen some of...
Constraints and Redundancy in Datalog
 IN PROCEEDINGS OF THE ELEVENTH SYMPOSIUM ON PRINCIPLES OF DATABASE SYSTEMS (PODS
, 1992
"... Two types of redundancies in datalog programs are considered. Redundancy based on reachability eliminates rules and predicates that do not participate in any derivation tree of a fact for the query predicate. Redundancy based on irrelevance is similar, but considers only minimal derivation trees, ..."
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Cited by 34 (15 self)
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Two types of redundancies in datalog programs are considered. Redundancy based on reachability eliminates rules and predicates that do not participate in any derivation tree of a fact for the query predicate. Redundancy based on irrelevance is similar, but considers only minimal derivation trees, that is, derivation trees having no pair of identical atoms, such that one is an ancestor of the other. Algorithms for detecting these redundancies are given, including the case of programs with constraint literals. These algorithms not only detect redundancies in the presence of constraints, but also push constraints from the given query and rules to the EDB predicates. Under certain assumptions discussed in the paper, the constraints are pushed to the EDB as tightly as possible.
A Closed Form Evaluation For Datalog Queries With Integer (GAP)Order Constraints
 Theoretical Computer Science
, 1993
"... : We provide a generalization of Datalog based on generalizing databases by adding integer order constraints to relational tuples. For Datalog queries with integer (gap)order constraints (denoted Datalog !Z ) we show that there is a closed form evaluation. We also show that the tuple recognition ..."
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Cited by 30 (8 self)
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: We provide a generalization of Datalog based on generalizing databases by adding integer order constraints to relational tuples. For Datalog queries with integer (gap)order constraints (denoted Datalog !Z ) we show that there is a closed form evaluation. We also show that the tuple recognition problem can be done in PTIME in the size of the generalized database, assuming that the size of the constants in the query is logarithmic in the size of the database. Note that the absence of negation is critical, Datalog : queries with integer order constraints can express any Turing computable function. 1 Introduction In this paper we consider a generalization of Datalog based on the notion of a constraint tuple. The important idea of a constraint tuple comes from constraint logic programming systems, e.g. CLP [14], Prolog III [4], and CHIP [8], and it generalizes the notion of a ground fact. This allows the declarative programming of new applications, including various combinatorial se...
Safe constraint queries
 In PODS'98
"... We extend some of the classical characterization theorems of relational database theory  particularly those related to query safety  to the context where database elements come with xed interpreted structure, and where formulae over elements of that structure can be used in queries. We show that ..."
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Cited by 27 (7 self)
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We extend some of the classical characterization theorems of relational database theory  particularly those related to query safety  to the context where database elements come with xed interpreted structure, and where formulae over elements of that structure can be used in queries. We show that the addition of common interpreted functions such as real addition and multiplication to the relational calculus preserves important characterization theorems of the relational calculus, and also preserves certain combinatorial properties of queries. Our main result of the rst kind is that there is a syntactic characterization of the collection of safe queries over the relational calculus supplemented by a wide class of interpreted functions  a class that includes addition, multiplication, and exponentiation  and that this characterization gives us an interpreted analog of the concept of rangerestricted query from the uninterpreted setting. Furthermore, our rangerestricted queries are particularly intuitive for the relational calculus with real arithmetic, and give a natural syntax for safe queries in the presence of polynomial functions. We use these characterizations to show that safety is decidable for Boolean combinations of conjunctive queries for a large class of interpreted structures. We show a dichotomy theorem that sets a polynomial bound on the growth of the output of a query that might refer to addition, multiplication and exponentiation. We apply the above results for nite databases to get results on constraint databases, representing potentially innite objects. We start by getting syntactic characterizations of the queries on constraint databases that preserve geometric conditions in the constraint data model. We consider classes of convex polytopes, polyhedra, and compact semilinear sets, the latter corresponding to many spatial applications. We show how to give an eective syntax to safe queries, and prove that for conjunctive queries the preservation properties are decidable. 1
Constraint Databases: A Survey
 Semantics in Databases, number 1358 in LNCS
, 1998
"... . Constraint databases generalize relational databases by finitely representable infinite relations. This paper surveys the state of the art in constraint databases: known results, remaining open problems and current research directions. The paper also describes a new algebra for databases with inte ..."
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Cited by 25 (3 self)
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. Constraint databases generalize relational databases by finitely representable infinite relations. This paper surveys the state of the art in constraint databases: known results, remaining open problems and current research directions. The paper also describes a new algebra for databases with integer order constraints and a complexity analysis of evaluating queries in this algebra. In memory of Paris C. Kanellakis 1 Introduction There is a growing interest in recent years among database researchers in constraint databases, which are a generalization of relational databases by finitely representable infinite relations. Constraint databases are parametrized by the type of constraint domains and constraint used. The good news is that for many parameters constraint databases leave intact most of the fundamental assumptions of the relational database framework proposed by Codd. In particular, 1. Constraint databases can be queried by constraint query languages that (a) have a semantics ba...
Domain Independence and the Relational Calculus
 Acta Informatica
, 1993
"... Several alternative semantics (or interpretations) of the relational (domain) calculus are studied here. It is shown that they all have the same expressive power, i.e., the selection of any of the semantics neither gains nor loses expressive power. Since the domain is potentially infinite, the answe ..."
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Cited by 22 (7 self)
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Several alternative semantics (or interpretations) of the relational (domain) calculus are studied here. It is shown that they all have the same expressive power, i.e., the selection of any of the semantics neither gains nor loses expressive power. Since the domain is potentially infinite, the answer to a relational calculus query is sometimes infinite (and hence not a relation). The following approaches which guarantee the finiteness of answers to queries are studied here: outputrestricted unlimited interpretation, domain independent queries, outputrestricted finite and countable invention, and limited interpretation. Of particular interest is the outputrestricted unlimited interpretation  although the output is restricted to the active domain of the input and query, the quantified variables range over the infinite underlying domain. While this is close to the intuitive interpretation given to calculus formulas, the naive approach to evaluating queries under this semantics calls ...
Speeding Up Inferences Using Relevance Reasoning: A Formalism and Algorithms
 ARTIFICIAL INTELLIGENCE
, 1997
"... Irrelevance reasoning refers to the process in which a system reasons about which parts of its knowledge are relevant (or irrelevant) to a specific query. Aside from its importance in speeding up inferences from large knowledge bases, relevance reasoning is crucial in advanced applications such a ..."
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Cited by 16 (3 self)
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Irrelevance reasoning refers to the process in which a system reasons about which parts of its knowledge are relevant (or irrelevant) to a specific query. Aside from its importance in speeding up inferences from large knowledge bases, relevance reasoning is crucial in advanced applications such as modeling complex physical devices and information gathering in distributed heterogeneous systems. This article presents a novel framework for studying the various kinds of irrelevance that arise in inference and efficient algorithms for relevance reasoning. We present a
Database Programming with Delayed Updates
 IN INTL. WORKSHOP ON DATABASE PROGRAMMING LANGUAGES
, 1991
"... There are a variety of advanced database features which require the ability to manipulate "virtual" database states along with the actual stored state; examples of this include rulebased triggers in active databases, support for hypothetical reasoning, and some concurrent transaction pr ..."
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Cited by 15 (8 self)
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There are a variety of advanced database features which require the ability to manipulate "virtual" database states along with the actual stored state; examples of this include rulebased triggers in active databases, support for hypothetical reasoning, and some concurrent transaction processing systems. This paper