A cost-based model and effective heuristic for repairing constraints by value modification

Abstract

Data integrated from multiple sources may contain inconsistencies that violate integrity constraints. The constraint repair problem attempts to find "low cost" changes that, when applied, will cause the constraints to be satisfied. While in most previous work repair cost is stated in terms of tuple insertions and deletions, we follow recent work to define a database repair as a set of value modifications. In this context, we introduce a novel cost framework that allows for the application of techniques from record-linkage to the search for good repairs. We prove that finding minimal-cost repairs in this model is NP-complete in the size of the database, and introduce an approach to heuristic repair-construction based on equivalence classes of attribute values. Following this approach, we define two greedy algorithms. While these simple algorithms take time cubic in the size of the database, we develop optimizations inspired by algorithms for duplicate-record detection that greatly improve scalability. We evaluate our framework and algorithms on synthetic and real data, and show that our proposed optimizations greatly improve performance at little or no cost in repair quality.

Analyses and Validation of Conditional Dependencies with Built-in Predicates

“…Second, we are developing effective algorithms for discovering cfd p s and cind p s, along the same lines as [10,18,15]. Third, we plan to extend the methods of [5,13] to repair data based on cfd p s and cind p s, instead of using cfds [13], traditional fds and inds [5], denial constraints [4,12], and aggregate constraints [16].…”

“…Methods have been developed for discovering cfds [10,18,15] and for repairing data based on either cfds [13], traditional fds and inds taken together [5], denial constraints [4,12], or aggregate constraints [16]. We defer the treatment of these topics for cfd p s and cind p s to future work.…”

CrowdAidRepair: A Crowd-Aided Interactive Data Repairing Method

“…The traditional category of methods relies on a variety of constraints including FDs [1,11], CFDs [4], Integrity Constraints [9] and Inclusion Dependencies (INCs) [1] to detect inconsistency (or conflicts) between data aroused by erroneous data, and then work on resolving all the conflicts with expecting to fix all erroneous data in this way [2,8,9]. For general textual databases, most work in this category use FD/CFDs for repairing as they are the constraints within a single relational table, while some other work uses INCs for repairing between multiple relational tables.…”

“…So far, various data repairing solutions have been developed to automatically detect and repair erroneous data in databases [12]. The main stream of rule-based solutions [2,8,9] rely on a variety of quality rules such as FD/CFDs [1,4,11] to detect violations and conflicts between data. By resolving these violations and conflicts, they expect to fix the erroneous data.…”

The consistency extractor system: Answer set programs for consistent query answering in databases

“…The adornments are propagated over the literals in the body of the rule (as for non-disjunctive rules), and also to the head literal R (x, y, t a ). Therefore, this rule becomes: 14 y, f a ). Now, the new adorned atoms R b f b (x, y, t a ), R b f b (x, y, f a ) also have to be processed, producing adornments on rules defining predicate R, and so on.…”