Incomplete object—a data model for design and planning applications

On the Computational Complexity of Minimal-Change Integrity Maintenance in Relational Databases

“…The need to accommodate violations of functional dependencies is one of the main motivations for considering disjunctive databases (studied, among others, by Imieliński, van der Meyden, Naqvi, and Vadaparty [53,54,61] and has led to various proposals in the context of data integration (Agarwal et al [3], Baral et al [10], Dung [32], and Lin and Mendelzon [58]). There seems to be an intriguing connection between relation repairs w.r.t.…”

“…Known tractable classes of first-order queries over disjunctive databases typically involve conjunctive queries and databases with restricted OR-objects [53,54]. In some cases, like in Example 3, the set of all repairs can be represented as a table with OR-objects.…”

Query Answering in Inconsistent Databases

“…This approach is limited to primary key functional dependencies and was subsequently generalized to other key functional dependencies by Dung [37]. In the same context, Baral et al [13,53] proposed to use disjunctive Datalog, and Lin and Mendelzon [79] tables with OR-objects [62,63]. Agarwal et al [2] introduced flexible relational algebra to query flexible relations, and Dung [37] introduced flexible relational calculus (a proper subset of the calculus can be translated to flexible relational algebra).…”

Scalar Aggregation in FD-Inconsistent Databases

“…Perhaps it is more natural for such queries to return a set of values, each corresponding to the value of the function in some repair. Along the same lines, one could represent such a set as an OR-object [12] or a C-table [11]. However, the interval-based representation is exponentially more compact than any explicit set-based representation.…”

“…A more comprehensive discussion can be found in [2]. The need to accommodate violations of functional dependencies is one of the main motivations for considering disjunctive databases [12,14] and has led to various proposals in the context of data integration [1,3,8,13]. A purely proof-theoretic notion of consistent query answer comes from Bry [6].…”