# Complexity of Consistent Query Answering in Databases under Cardinality-Based and Incremental Repair Semantics (extended version)

arXiv: https://arxiv.org/abs/1605.07159 · HTML: https://mlsanity.com/paper/1605.07159/

## Key facts

- Cited by 12 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 23 May 2016.

## Built on by (most cited first, 12 of 12)

- [From Database Repairs to Causality in Databases and Beyond](https://mlsanity.com/paper/2306.09374/) (2023)
- [Score-Based Explanations in Data Management and Machine Learning: An Answer-Set Programming Approach to Counterfactual Analysis](https://mlsanity.com/paper/2106.10562/) (2021)
- [Attribution-Scores in Data Management and Explainable Machine Learning](https://mlsanity.com/paper/2308.00184/) (2023)
- [Cost-Based Semantics for Querying Inconsistent Weighted Knowledge Bases](https://mlsanity.com/paper/2407.20754/) (2024)
- [On the complexity of finding set repairs for data-graphs](https://mlsanity.com/paper/2206.07504/) (2022)
- [A Rule-Based Approach to Specifying Preferences over Conflicting Facts and Querying Inconsistent Knowledge Bases](https://mlsanity.com/paper/2508.07742/) (2025)
- [Sufficient Explanations in Databases and their Connections to Database Repairs](https://mlsanity.com/paper/2511.15623/) (2025)
- [Second-Order Specifications and Quantifier Elimination for Consistent Query Answering in Databases](https://mlsanity.com/paper/2108.08423/) (2021)
- [Consistent Query Answering for Existential Rules with Closed Predicates](https://mlsanity.com/paper/2401.05743/) (2024)
- [Computational Complexity of Preferred Subset Repairs on Data-Graphs](https://mlsanity.com/paper/2402.09265/) (2024)
- [Inconsistent Databases and Argumentation Frameworks with Collective Attacks](https://mlsanity.com/paper/2605.03954/) (2026)
- [Reconciling Consistency-Based Diagnosis with Actual-Causality-Based Explanations](https://mlsanity.com/paper/2605.08688/) (2026)

## Abstract (arXiv)

A database D may be inconsistent wrt a given set IC of integrity constraints. Consistent Query Answering (CQA) is the problem of computing from D the answers to a query that are consistent wrt IC . Consistent answers are invariant under all the repairs of D, i.e. the consistent instances that minimally depart from D. Three classes of repair have been considered in the literature: those that minimize set-theoretically the set of tuples in the symmetric difference; those that minimize the changes of attribute values, and those that minimize the cardinality of the set of tuples in the symmetric difference. The latter class has not been systematically investigated. In this paper we obtain algorithmic and complexity theoretic results for CQA under this cardinality-based repair semantics. We do this in the usual, static setting, but also in a dynamic framework where a consistent database is affected by a sequence of updates, which may make it inconsistent. We also establish comparative results with the other two kinds of repairs in the dynamic case.