Integrity Constraints Revisited: From Exact to Approximate Implication

Integrity constraints such as functional dependencies (FD) and multi-valued dependencies (MVD) are fundamental in database schema design. Likewise, probabilistic conditional independences (CI) are crucial for reasoning about multivariate probability distributions. The implication problem studies whe...

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Main Authors: Batya Kenig, Dan Suciu
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2022-01-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/6925/pdf
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author Batya Kenig
Dan Suciu
author_facet Batya Kenig
Dan Suciu
author_sort Batya Kenig
collection DOAJ
description Integrity constraints such as functional dependencies (FD) and multi-valued dependencies (MVD) are fundamental in database schema design. Likewise, probabilistic conditional independences (CI) are crucial for reasoning about multivariate probability distributions. The implication problem studies whether a set of constraints (antecedents) implies another constraint (consequent), and has been investigated in both the database and the AI literature, under the assumption that all constraints hold exactly. However, many applications today consider constraints that hold only approximately. In this paper we define an approximate implication as a linear inequality between the degree of satisfaction of the antecedents and consequent, and we study the relaxation problem: when does an exact implication relax to an approximate implication? We use information theory to define the degree of satisfaction, and prove several results. First, we show that any implication from a set of data dependencies (MVDs+FDs) can be relaxed to a simple linear inequality with a factor at most quadratic in the number of variables; when the consequent is an FD, the factor can be reduced to 1. Second, we prove that there exists an implication between CIs that does not admit any relaxation; however, we prove that every implication between CIs relaxes "in the limit". Then, we show that the implication problem for differential constraints in market basket analysis also admits a relaxation with a factor equal to 1. Finally, we show how some of the results in the paper can be derived using the I-measure theory, which relates between information theoretic measures and set theory. Our results recover, and sometimes extend, previously known results about the implication problem: the implication of MVDs and FDs can be checked by considering only 2-tuple relations.
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spelling doaj.art-04e2ad0d45d34300a58907bffcd4e2532024-03-08T10:36:53ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742022-01-01Volume 18, Issue 110.46298/lmcs-18(1:5)20226925Integrity Constraints Revisited: From Exact to Approximate ImplicationBatya KenigDan SuciuIntegrity constraints such as functional dependencies (FD) and multi-valued dependencies (MVD) are fundamental in database schema design. Likewise, probabilistic conditional independences (CI) are crucial for reasoning about multivariate probability distributions. The implication problem studies whether a set of constraints (antecedents) implies another constraint (consequent), and has been investigated in both the database and the AI literature, under the assumption that all constraints hold exactly. However, many applications today consider constraints that hold only approximately. In this paper we define an approximate implication as a linear inequality between the degree of satisfaction of the antecedents and consequent, and we study the relaxation problem: when does an exact implication relax to an approximate implication? We use information theory to define the degree of satisfaction, and prove several results. First, we show that any implication from a set of data dependencies (MVDs+FDs) can be relaxed to a simple linear inequality with a factor at most quadratic in the number of variables; when the consequent is an FD, the factor can be reduced to 1. Second, we prove that there exists an implication between CIs that does not admit any relaxation; however, we prove that every implication between CIs relaxes "in the limit". Then, we show that the implication problem for differential constraints in market basket analysis also admits a relaxation with a factor equal to 1. Finally, we show how some of the results in the paper can be derived using the I-measure theory, which relates between information theoretic measures and set theory. Our results recover, and sometimes extend, previously known results about the implication problem: the implication of MVDs and FDs can be checked by considering only 2-tuple relations.https://lmcs.episciences.org/6925/pdfcomputer science - databases
spellingShingle Batya Kenig
Dan Suciu
Integrity Constraints Revisited: From Exact to Approximate Implication
Logical Methods in Computer Science
computer science - databases
title Integrity Constraints Revisited: From Exact to Approximate Implication
title_full Integrity Constraints Revisited: From Exact to Approximate Implication
title_fullStr Integrity Constraints Revisited: From Exact to Approximate Implication
title_full_unstemmed Integrity Constraints Revisited: From Exact to Approximate Implication
title_short Integrity Constraints Revisited: From Exact to Approximate Implication
title_sort integrity constraints revisited from exact to approximate implication
topic computer science - databases
url https://lmcs.episciences.org/6925/pdf
work_keys_str_mv AT batyakenig integrityconstraintsrevisitedfromexacttoapproximateimplication
AT dansuciu integrityconstraintsrevisitedfromexacttoapproximateimplication