Results 1 - 10 of 152

The ramification and qualification problems in temporal databases

by Nick Papadakis, Dimitris Plexousakis - in: Proceedings of the 2nd Hellenic Conference on AI, Lecture Notes on Artificial Intelligent , 2002
"... Abstract. The ramification and qualification problems are two infamous, hard and ever present problems in databases and, more generally, in systems exhibiting a dynamic behavior. The ramification problem refers to determining the indirect effects of actions, whereas the qualification problem refers ..."
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to determining the preconditions which must hold prior to the execution of an action. A solution to these problems in database systems permits reasoning about the dynamics of databases and allows proving consistency properties. These two problems become increasingly complex in temporal databases

Automated selection of materialized views and indexes in sql databases

by Sanjay Agrawal, Surajit Chaudhuri, Vivek Narasayya - in proc. VLDB ’00 , 2000
"... Automatically selecting an appropriate set of materialized views and indexes for SQL databases is a non-trivial task. A judicious choice must be cost-driven and influenced by the workload experienced by the system. Although there has been work in materialized view selection in the context of multidi ..."
Abstract - Cited by 142 (11 self) - Add to MetaCart
of multidimensional (OLAP) databases, no past work has looked at the problem of building an industry-strength tool for automated selection of materialized views and indexes for SQL workloads. In this paper, we present an end-to-end solution to the problem of selecting materialized views and indexes. We describe

Actions with Duration and Constraints: the Ramification Problem in Temporal Databases

by Nikos Papadakis, Dimitris Plexousakis - In: ICTAI ’02: Proceedings of the 14th IEEE International Conference on Tools with Artificial Intelligence (ICTAI’02 , 2003
"... The ramification problem is a hard and ever present problem in systems exhibiting a dynamic behavior. The area of temporal databases in particular is still lacking satisfactory solutions to the ramification problem. ..."
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The ramification problem is a hard and ever present problem in systems exhibiting a dynamic behavior. The area of temporal databases in particular is still lacking satisfactory solutions to the ramification problem.

Point-based Temporal Extensions of SQL and their Efficient Implementation

by David Toman - In Temporal Databases: Research and Practice , 1998
"... . This chapter introduces a new approach to temporal extensions of SQL. The main difference from most of the current proposals is the use single time points, rather than intervals or various other complexvalues for references to time, while still achieving efficient query evaluation. The proposed la ..."
Abstract - Cited by 19 (2 self) - Add to MetaCart
language, SQL/TP, extends the syntax of SQL/92 to handle temporal data in a natural way: it adds a single data type to represent a linearly ordered universe of time instants. The semantics of the new language naturally extends the standard SQL semantics and eliminates or fixes many of the problems

The Ramification Problem in Temporal Databases: Concurrent Execution with Conflicting Constraints

by Nikos Papadakis, Grigoris Antoniou, Dimitris Plexousakis
"... In this paper we study the ramification problem in the setting of temporal databases. Standard solutions from the literature on reasoning about action are inadequate because they rely on the assumptions that fluents persist and actions have effects on the subsequent situation only. We provide a solu ..."
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In this paper we study the ramification problem in the setting of temporal databases. Standard solutions from the literature on reasoning about action are inadequate because they rely on the assumptions that fluents persist and actions have effects on the subsequent situation only. We provide a

Implementation of Cross-platform Language between SQL and NoSQL Database Systems

by Kenechukwu K Okeke , Virginia E Ejiofor
"... ABSTRACT This work proposes to look into the construct of SQL (structured Query Language) and NoSQL (Not only SQL) systems. This will help proffer a framework that guarantees interoperability across board for SQL and NoSQL platforms. This research is being carried out to find a lasting solution to ..."
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ABSTRACT This work proposes to look into the construct of SQL (structured Query Language) and NoSQL (Not only SQL) systems. This will help proffer a framework that guarantees interoperability across board for SQL and NoSQL platforms. This research is being carried out to find a lasting solution

Addressing the Ramification Problem in a Temporal Context: the case of Concurrent Actions

by Nikos Papadakis, Dimitris Plexousakis
"... The ramification problem is a hard and ever present problem in systems exhibiting a dynamic behavior. The area of temporal databases in particular is still lacking satisfactory solutions to the ramification problem. In this paper, we address the problem for the concurrent execution of both instantan ..."
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The ramification problem is a hard and ever present problem in systems exhibiting a dynamic behavior. The area of temporal databases in particular is still lacking satisfactory solutions to the ramification problem. In this paper, we address the problem for the concurrent execution of both

Evaluation of a Constraint-Based Tutor for a Database Language

by Stellan Ohlsson - International Journal of Artificial Intelligence in Education , 1999
"... Abstract: We propose a novel approach to intelligent tutoring in which feedback messages are associated with constraints on correct problem solution. The knowledge state of the student is represented by the constraints that he or she does and does not violate during problem solving. Constraint-base ..."
Abstract - Cited by 122 (42 self) - Add to MetaCart
-based tutoring has been implemented in SQL-Tutor, an intelligent tutoring system for teaching the database query language SQL. Empirical evaluation shows that (a) students find the system easy to use, and (b) they do better on a subsequent classroom examination than peers without experience with the system

Physical database design for relational databases

by S. Finkelstein, M. Schkolnick, P. Tiberio - ACM Transactions on Database Systems , 1988
"... This paper describes the concepts used in the implementation of DBDSGN, an experimental physical design tool for relational databases developed at the IBM San Jose Research Laboratory. Given a workload for System R (consisting of a set of SQL statements and their execution frequencies), DBDSGN sugge ..."
Abstract - Cited by 88 (0 self) - Add to MetaCart
This paper describes the concepts used in the implementation of DBDSGN, an experimental physical design tool for relational databases developed at the IBM San Jose Research Laboratory. Given a workload for System R (consisting of a set of SQL statements and their execution frequencies), DBDSGN

Visualizing Queries on Databases of Temporal Histories: New metaphors and . . .

by Chittaro, Luca Chittaro A, Carlo Combi B, Carlo Combi B
"... by a wide base of users is given by its user interface. After analyzing and discussing the state of the art for the visualization of temporal intervals and relations, this paper proposes three new solutions to the problem of visualizing temporal intervals and their relations for querying databases c ..."
Abstract - Cited by 27 (0 self) - Add to MetaCart
by a wide base of users is given by its user interface. After analyzing and discussing the state of the art for the visualization of temporal intervals and relations, this paper proposes three new solutions to the problem of visualizing temporal intervals and their relations for querying databases
Results 1 - 10 of 152