Godfrey P., Minker J., Novik L., An Architecture for a Cooperative Database System, Applications of Databases, (eds.: W. Litwin, T. Risch), Lecture Notes in Computer Science 819, 1994, pp. 2-24.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....(the answer set) is returned. in CDBS this query answer paradigm is augmented to allow the system to relax a query in some cases (e.g. when a query fails) Then an approximate answer may be provided. Relaxation of a query may consist in rewriting it into a set of more general related queries [2,3]. in the paper, we discuss approximate answers through relaxation of semantics of the underlying query language. in particular, we propose a weaker interpretation of the symbol = in atomic formulas. instead of equality, the symbol might be interpreted as a partial ordering relation (in child ....

Godfrey P., Minker J., Novik L., An Architecture for a Cooperative Database System, Applications of Databases, (eds.: W. Litwin, T. Risch), Lecture Notes in Computer Science 819, 1994, pp. 2-24.

....objects, databases 1. Introduction in conventional databases, a query written in a formal query language is accepted, evaluated against a database, and the complete set of data satisfying the query (the answer set) is returned. in some systems, however, e.g. in cooperative database systems [8,9,10,12,15], or in multilevel database [4,10] this query answer paradigm is augmented to allow the system to relax a query (e.g. when a query fails or if access privileges of the user are too low) Then an approximate answer may be provided. Relaxation of a query may consist in rewriting it into a set of ....

.... 1: 101 102 103 104 105 106 Storel [102, 103] Address 1 Warsaw Parts 1 Computer parts Storel [105, 106] Addressl Poznafi Partsl Car parts , since: 101 1,104 8, 102, 103] 2, 3] Addressl L Address, Partsl L Parts, Computer parts 4, 5 , 105, 106] [9, 10], Poznafi [11, 12] Car parts 13 . Thus, the following query v I Store(x) 3 v x .Parts(v) v = Pentium ili , returning 1 , can be generalized to the query w I Storel(y) 3 w y .Partsl(w) w = Computer part which returns 101 . Theorem 3. Let q, q be ....

Godfrey P., Minker J., Novik L., An Architecture for a Cooperative Database System, Applications of Databases, (eds.: W. Litwin, T. Risch), Lecture Notes in Computer Science 819, 1994, pp. 2-24.

....on experiences gained with the implementation. We indicate which of the investigated ideas are in fact advantageous for query optimization. 1. 3 Further Related Work In addition to the work on Web query languages, work on query optimization based on database integrity constraints is also relevant [13, 9]. With regard to rule based query optimization, one can distinguish between application independent transformation rules and application specific ones. The latter can be further classified into approaches where rules contain hardcoded application specific knowledge and those where the ....

Parke Godfrey, Jack Minker, and Lev Novik. An Architecture for a Cooperative Database System. In Witold Litwin and Tore Risch, editors, Proceedings of First International Conference on Applications of Databases, number 819 in Lecture Notes in Computer Science, pages 3--24. Springer-Verlag, June 1994.

....that can be composed of words from geographic domain dictionaries and thesauruses using a structured editor. The SQL style user interfaces for dynamic maps are not human centered systems because of the necessity of users knowledge for database schemata and query language grammars [7] 10] [11]. Our approach adopts the combinations of only natural words stored in knowledge bases, including dictionaries, thesauruses and rule bases, for geographic applications to describe ad hoc queries where components are some words, ad 2 IEICE TRANS. FUNDAMENTALS, VOL. E00 X, NO. x x 1996 Fig. 1 A ....

P. Godfrey, J. Minker, L. Novik, "An Architecture for a Cooperative Database System", Proc. of 1st Int'l Conf. on Applications of Databases (Witold Litwin, Tore Rische Eds.), Lecture Note in Computer Science 819, Springer-Verlag, pp. 3 -- 22, Jun. 1994.

....containing the further explanation. In turn this explanation may be interacted with. 6.0 Comparison to Previous Work Few Cooperative Information Systems[5] have included an explanation facility. McCoy [8] generated explanations to clear up a user s misconceptions of a database schema. The CARMIN [6] system includes an integrated explanation and answer presentation system. In this system explanations are based on the proof path used by a PROLOG meta interpreter. Aspects of what to include and how to coordinate these explanations were also investigated. In contrast to these approaches, the ....

Godfrey, P., Minker, J., Novik, L. An Architecture for a Cooperative Database Systems. International Conference on Applications of Databases, June 1994.

....we report on implementation experiences. We indicate which of the investigated ideas are in fact advantageous for query optimization. 1. 3 Further Related Work In addition to the work on Web query languages, work on query optimization based on database integrity constraints is also relevant [14, 9]. With regard to rule based query optimization, one can distinguish between application independent transformation rules and application specific ones. The latter can be further classified into approaches where rules contain hardcoded application specific knowledge and those where the ....

Parke Godfrey, Jack Minker, and Lev Novik. An Architecture for a Cooperative Database System. In Witold Litwin and Tore Risch, editors, Proceedings of First International Conference on Applications of Databases, number 819 in Lecture Notes in Computer Science, pages 3--24. Springer-Verlag, June 1994.

....a non trivial task, and is a research topic in its own right. It is not our focus here. For this paper we assume this step, and the set of null unfoldings is an input to our algorithms. For edification of the reader, we briefly sketch an approach to finding null unfoldings. In the Carmin project [4, 3], a project to provide cooperative responses to database queries in addition to their answer sets, we have explored methods to identify the null unfoldings of a query. The general approach that we have developed is as follows. ffl Rewrite each IC by replacing its empty head with the special ....

P. Godfrey, J. Minker, and L. Novik. An architecture for a cooperative database system. In W. Litwin and T. Risch, eds., Proc. of the 1st Int. Conf. on Applications of Databases, LNCS 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

....by Gal [19] identifies the integrity constraints that guarantee failure, and provides a response to the user based on them. Gal also recognized the need to provide an MCS, but did not address how to identify the minimal subqueries with misconceptions. See the survey [17] for more background. In [18, 24] the design and implementation of a cooperative database system are discussed, in which miscon 8 A generalization lattice for a query is not necessarily finite, as is the subquery lattice. June 1997 Minimization in Cooperative Response Godfrey p. 7 of 46 breadth first depth first top down ....

P. Godfrey, J. Minker, and L. Novik. An architecture for a cooperative database system. In W. Litwin and T. Risch, editors, Proceedings of the First International Conference on Applications of Databases, Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

....nodes in the query tree. 7 Estimating the sizes of intermediate nodes based on the sizes of the tree leaves may be very unreliable for any U 2 S, N [ S) 0 fUg is not a cover of the query. Techniques from the Carmin System can be used to determine the set of null unfoldings, N , for a query [5, 4]. Carmin is a cooperative database system, which provides cooperative responses to queries, in addition to the answer sets. If Carmin can find a set of null unfoldings N for a query which is a cover of the query, and each such null unfolding is provably null, the query is said to be a complex ....

....introduction) should be developed and tested. Second, the algorithms for join elimination presented here should be generalized to work for databases with resursion and negation (in queries, rules and ICs) We intend to implement the algorithms on the testbed provided by the Carmin system [4, 5]. We plan to experiment with large databases to determine the conditions under which these algorithms perform well, and when to use one method over another. ....

Parke Godfrey, Jack Minker, and Lev Novik. An architecture for a cooperative database system. In Witold Litwin and Tore Risch, editors, Proceedings of the First International Conference on Applications of Databases, Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

.... domain constraint that states that all employees are over sixteen years old can be written as: A 16 ( employee (age : A) 4) We employ for convenience an attribute extended DATALOG, or fielded DATALOG, that uses attribute names, as does the relational model, to be understood in the obvious way [49]. This frees us from the inconvenience of notation in Prolog and DATALOG in which attribute names are not expressed, so only the position of a value in an atom indicates which attribute it fills. In fielded DATALOG, the slots for any attributes not mentioned in an atom are assumed to be filled ....

....and are atoms or (default) negations of atoms if default negation is part of the (normal) database. For the three IC given above, the 8 This field notation for DATALOG is merely syntactic convenience. It is easy to implement, for instance on top of Prolog. and is used by the Carmin system [49]. December 1997 ICs: Semantics and Applications Godfrey, Grant, Gryz, Minker p. 9 corresponding denial constraints are: employee (age : A) A 16. 4 0 ) employee (name : N,address : P 1 ) 1 0 ) employee (name : N,address : P 2 ) P 1 6= P 2 . employee (name : N, address : P, ....

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P. Godfrey, J. Minker, and L. Novik. An architecture for a cooperative database system. In W. Litwin and T. Risch, editors, Proceedings of the First International Conference on Applications of Databases, Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

....is found that does not imply a cache expression, the algorithm immediately halts. As there should not be many such most general unfoldings or many such most general proofs this procedure seems tractable in average case. In practice too, the unfold refold algorithm has shown good performance [14], The algorithm was initially developed for, and is used in, a system called Carmin, which detects when queries must fail due to the database s integrity constraints. 5 Conclusions and Future Work In this paper, we presented a logical framework for SQC. We specified conditions to determine when ....

P. Godfrey, J. Minker, and L. Novik. An architecture for a cooperative database system. In W. Litwin and T. Risch, editors, Proceedings of the First International Conference on Applications of Databases, Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

....relaxed alternatives the system provides, however, better resolve (remove) the semantic conflicts that cause the original query to be a misconception. Otherwise, the relaxation choices may be misconceptions too. In such a case, the relaxation facility could be patently unhelpful to the user. In [Godfrey et al. 1994], we consider such issues, and advocate the necessity for a general cooperative system to coordinate the cooperative behaviors it enables. Other techniques for cooperative answering create knowledge in an attempt to disambiguate or explain the situation for the user. One such important technique ....

....with finding the minimal failing subqueries (MFSs) of the query ( Godfrey, 1997b] Janas, 1979] Janas, 1981] and [Kaplan, 1981] We advocate doing this when the query failed and was first determined not to be a misconception. Otherwise, the misconception ought to be explained instead [Godfrey et al. 1994]. It is cooperative to focus on the part of the query that fails. Thus the user knows what information is not in the database and can appropriately revise what he or she is seeking. Consider a valid variant of the misconception query from before: Q: in patient (name : P, ward : maternity) ....

Godfrey, P., Minker, J., and Novik, L. (1994). An architecture for a cooperative database system. In Litwin, W. and Risch, T., editors, Proceedings of the First International Conference on Applications of Databases (ADB'94), Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden.

....by Gal [16] identifies the integrity constraints that guarantee failure, and provides a response to the user based on them. Gal also recognized the need to provide an MCS, but did not address how to identify the minimal subqueries with misconceptions. See the survey [14] for more background. In [15, 21] the design and implementation of a cooperative database system are discussed, in which misconception detection and explanation are key components. In this system, all three problems, MFS, MSS, and MCS, are to be addressed. 3 Analysis Finding a Minimal Failing Subquery At first consideration, ....

P. Godfrey, J. Minker, and L. Novik. An architecture for a cooperative database system. In W. Litwin and T. Risch, editors, Proceedings of the First International Conference on Applications of Databases, Lecture Notes in Computer Science 819, pages 3--24. Springer Verlag, Vadstena, Sweden, June 1994.

No context found.

P. Godfrey, J. Minker, L. Novik, "An Architecture for a Cooperative Database System", Proc. of 1st Int'l Conf. on Applications of Databases (Witold Litwin, Tore Rische Eds.), Lecture Note in Computer Science 819, Springer-Verlag, pp. 3 -- 22, Jun. 1994.

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