TY - JOUR A1 - Koumarelas, Ioannis A1 - Papenbrock, Thorsten A1 - Naumann, Felix T1 - MDedup BT - duplicate detection with matching dependencies JF - Proceedings of the VLDB Endowment N2 - Duplicate detection is an integral part of data cleaning and serves to identify multiple representations of same real-world entities in (relational) datasets. Existing duplicate detection approaches are effective, but they are also hard to parameterize or require a lot of pre-labeled training data. Both parameterization and pre-labeling are at least domain-specific if not dataset-specific, which is a problem if a new dataset needs to be cleaned. For this reason, we propose a novel, rule-based and fully automatic duplicate detection approach that is based on matching dependencies (MDs). Our system uses automatically discovered MDs, various dataset features, and known gold standards to train a model that selects MDs as duplicate detection rules. Once trained, the model can select useful MDs for duplicate detection on any new dataset. To increase the generally low recall of MD-based data cleaning approaches, we propose an additional boosting step. Our experiments show that this approach reaches up to 94% F-measure and 100% precision on our evaluation datasets, which are good numbers considering that the system does not require domain or target data-specific configuration. Y1 - 2020 U6 - https://doi.org/10.14778/3377369.3377379 SN - 2150-8097 VL - 13 IS - 5 SP - 712 EP - 725 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Schirmer, Philipp A1 - Papenbrock, Thorsten A1 - Koumarelas, Ioannis A1 - Naumann, Felix T1 - Efficient discovery of matching dependencies JF - ACM transactions on database systems : TODS N2 - Matching dependencies (MDs) are data profiling results that are often used for data integration, data cleaning, and entity matching. They are a generalization of functional dependencies (FDs) matching similar rather than same elements. As their discovery is very difficult, existing profiling algorithms find either only small subsets of all MDs or their scope is limited to only small datasets. We focus on the efficient discovery of all interesting MDs in real-world datasets. For this purpose, we propose HyMD, a novel MD discovery algorithm that finds all minimal, non-trivial MDs within given similarity boundaries. The algorithm extracts the exact similarity thresholds for the individual MDs from the data instead of using predefined similarity thresholds. For this reason, it is the first approach to solve the MD discovery problem in an exact and truly complete way. If needed, the algorithm can, however, enforce certain properties on the reported MDs, such as disjointness and minimum support, to focus the discovery on such results that are actually required by downstream use cases. HyMD is technically a hybrid approach that combines the two most popular dependency discovery strategies in related work: lattice traversal and inference from record pairs. Despite the additional effort of finding exact similarity thresholds for all MD candidates, the algorithm is still able to efficiently process large datasets, e.g., datasets larger than 3 GB. KW - matching dependencies KW - functional dependencies KW - dependency discovery KW - data profiling KW - data matching KW - entity resolution KW - similarity measures Y1 - 2020 U6 - https://doi.org/10.1145/3392778 SN - 0362-5915 SN - 1557-4644 VL - 45 IS - 3 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Birnick, Johann A1 - Bläsius, Thomas A1 - Friedrich, Tobias A1 - Naumann, Felix A1 - Papenbrock, Thorsten A1 - Schirneck, Friedrich Martin T1 - Hitting set enumeration with partial information for unique column combination discovery JF - Proceedings of the VLDB Endowment N2 - Unique column combinations (UCCs) are a fundamental concept in relational databases. They identify entities in the data and support various data management activities. Still, UCCs are usually not explicitly defined and need to be discovered. State-of-the-art data profiling algorithms are able to efficiently discover UCCs in moderately sized datasets, but they tend to fail on large and, in particular, on wide datasets due to run time and memory limitations.
In this paper, we introduce HPIValid, a novel UCC discovery algorithm that implements a faster and more resource-saving search strategy. HPIValid models the metadata discovery as a hitting set enumeration problem in hypergraphs. In this way, it combines efficient discovery techniques from data profiling research with the most recent theoretical insights into enumeration algorithms. Our evaluation shows that HPIValid is not only orders of magnitude faster than related work, it also has a much smaller memory footprint. Y1 - 2020 U6 - https://doi.org/10.14778/3407790.3407824 SN - 2150-8097 VL - 13 IS - 11 SP - 2270 EP - 2283 PB - Association for Computing Machinery CY - [New York, NY] ER -