Updating databases with incomplete information

Suppose one wishes to construct, use, and maintain a database of facts about the real world, even though the state of that world is only partially known. In the AI domain, this problem arises when an agent has a base set of beliefs that reflect partial knowledge about the world, and then tries to incorporate new, possibly contradictory knowledge into this set of beliefs. In the database domain, one facet of this situation is the well-known null values problem. We choose to represent such a database as a logical theory, and view the models of the theory as representing possible states of the world that are consistent with all known information. How can new information be incorporated into the database? For example, given the new information that "b or c is true," how can one get rid of all outdated information about b and c, add the new information, and yet in the process not disturb any other information in the database? In current-day database management systems, the burden of determining exactly what to add and remove from the database is placed on the user. Our research has produced a formal method of specifying the desired change intensionally, by stating a well-formed formula that the state of the world is now known to satisfy. The database update algorithms we provide will automatically accomplish that change. Our approach embeds the incomplete database and the incoming information in the language of mathematical logic, and gives formal definitions of the semantics of our update operators, along with proofs of correctness for their associated algorithms. We assess the computational complexity of the algorithms, and propose a means of lazy evaluation to avoid undesirable expense during execution of updates. We also examine means of enforcing integrity constraints as the database is updated. This thesis also examines the question of choices of semantics for update operators for databases with incomplete information, and proposes a framework for evaluation of competing candidate semantics. Several candidate semantics are evaluated with respect to that framework. A experimental implementation of our method has been constructed, and we include the results of test runs on a range of patterns of queries and updates.

[1]  Moshe Y. Vardi Querying Logical Databases , 1986, J. Comput. Syst. Sci..

[2]  J. D. Uiiman,et al.  Principles of Database Systems , 2004, PODS 2004.

[3]  Keith L. Clark,et al.  Negation as Failure , 1987, Logic and Data Bases.

[4]  Stephen Todd,et al.  Automatic Constraint Maintenance and Updating Defined Relations , 1977, IFIP Congress.

[5]  Jon Doyle,et al.  A Truth Maintenance System , 1979, Artif. Intell..

[6]  Arthur M. Keller,et al.  Algorithms for translating view updates to database updates for views involving selections, projections, and joins , 1985, PODS.

[7]  Raymond Reiter,et al.  A Theory of Diagnosis from First Principles , 1986, Artif. Intell..

[8]  Marianne Winslett,et al.  Is Belief Revision Harder Than You Thought? , 1986, AAAI.

[9]  Vladimir Lifschitz,et al.  Closed-World Databases and Circumscription , 1987, Artif. Intell..

[10]  Arthur M. Keller,et al.  On the Use of an Extended Relational Model to Handle Changing Incomplete Information , 1985, IEEE Transactions on Software Engineering.

[11]  R. Loui,et al.  Change in View , 1987, Artif. Intell..

[12]  Lotfi A. Zadeh,et al.  Approximate Reasoning Based on Fuzzy Logic , 1979, IJCAI.

[13]  Herbert B. Enderton,et al.  A mathematical introduction to logic , 1972 .

[14]  Arthur M. Keller,et al.  Updates to Relational Databases Through Views Involving Joins , 1982, International Conference on Data and Knowledge Bases.

[15]  Ryszard S. Michalski,et al.  Variable Precision Logic , 1986, Artif. Intell..

[16]  Umeshwar Dayal,et al.  On the correct translation of update operations on relational views , 1982, TODS.

[17]  Raymond Reiter,et al.  Equality and Domain Closure in First-Order Databases , 1980, JACM.

[18]  Raymond Reiter,et al.  Towards a Logical Reconstruction of Relational Database Theory , 1982, On Conceptual Modelling.

[19]  James Davidson,et al.  A natural language interface for performing database updates , 1984, 1984 IEEE First International Conference on Data Engineering.

[20]  Andreas Weber,et al.  Updating Propositional Formulas , 1986, Expert Database Conf..

[21]  Christos H. Papadimitriou,et al.  The Theory of Database Concurrency Control , 1986 .

[22]  Yannis Vassiliou,et al.  Null values in data base management a denotational semantics approach , 1979, SIGMOD '79.

[23]  Nils J. Nilsson,et al.  Probabilistic Logic * , 2022 .

[24]  Carlo Zaniolo,et al.  Database relations with null values , 1982, J. Comput. Syst. Sci..

[25]  Gio Wiederhold,et al.  Database Design , 1977 .

[26]  John McCarthy,et al.  Circumscription - A Form of Non-Monotonic Reasoning , 1980, Artif. Intell..

[27]  A M Keller On 'Update Semantics and Relational Views'. , 1984 .

[28]  Hector J. Levesque,et al.  Foundations of a Functional Approach to Knowledge Representation , 1984, Artif. Intell..

[29]  Donald D. Chamberlin,et al.  SEQUEL 2: A Unified Approach to Data Definition, Manipulation, and Control , 1976, IBM J. Res. Dev..

[30]  Marianne Winslett Updating Logical Databases Containing Null Values , 1986, ICDT.

[31]  Tomasz Imielinski,et al.  Incomplete Information in Relational Databases , 1984, JACM.