Abstract: Computer implemented methods for identifying denial constraints are provided herein. The denial constraints can be used with a database schema R. A predicate space P can be generated for an instance I in the schema R. An evidence set EviI can be generated. The evidence set EviI can include sets of satisfied predicates in the predicate space P for each instance I. A minimal set of predicates can be identified for the evidence set EviI. Valid denial constraints can be identified from the minimal set by inverting the predicates in the minimal set.

Abstract: A system for checking data for errors, the system comprising a checking module operable to check tuples of data stored in a target database for errors, the tuples in the target database originating from the output of at least one query transformation module which applies a query transformation to tuples of data from at least one data source an identification module operable to identify a problematic tuple from a data source that produces an error in the target database, the identification module being operable to quantify the contribution of the problematic tuple in producing the error in the target database, and a description generation module operable to generate a descriptive query which represents at least one of errors identified by the checking module in the target database which are produced by the at least one query transformation module, and problematic tuples identified in a data source by the identification module.

Abstract: A method for integrating data into a database comprises storing data comprising a plurality of records which each comprise a plurality of attributes; analyzing a sample of records from the plurality of records by: identifying duplicate pairs of records in the sample records; analyzing each attribute of each record of the duplicate pairs of records to identify a respective attribute condition which is indicative that the pairs of records are duplicates; wherein the method further comprises: comparing each attribute of a record with the respective attribute condition and, if the attribute satisfies the attribute condition, allocating the record to a disjoint group which comprises records with an attribute that satisfies the same respective attribute condition; identifying duplicate pairs of records in the records in each disjoint group; identifying duplicate pairs of records in records that are not allocated to a disjoint group; and consolidating each duplicate pair of records into one consolidated record and s

Abstract: A system for checking data for errors, the system comprising a checking module operable to check tuples of data stored in a target database for errors, the tuples in the target database originating from the output of at least one query transformation module which applies a query transformation to tuples of data from at least one data source an identification module operable to identify a problematic tuple from a data source that produces an error in the target database, the identification module being operable to quantify the contribution of the problematic tuple in producing the error in the target database, and a description generation module operable to generate a descriptive query which represents at least one of errors identified by the checking module in the target database which are produced by the at least one query transformation module, and problematic tuples identified in a data source by the identification module.

Abstract: A computer implemented method for repairing records of a database, comprises determining a first set of records of the database which violate a functional dependency of the database, determining a second set of records of the database comprising duplicate records, computing a cost metric representing a measure for the cost of mutually dependently modifying records in the first and second sets, modifying records in the first and second sets on the basis of the cost metric to provide a modified database instance.

Abstract: A computer-implemented method comprising partitioning data representing an input instance of a database including multiple tuples into multiple fragments of tuples, detecting tuples which violate a data quality specification in respective ones of the fragments, selecting a data cleaning asset on the basis of characteristics of errors in detected tuples for a fragment and based on declared asset capabilities, assigning a selected data cleaning asset to the fragment, the selected data cleaning asset to provide a set of candidate corrections for the detected tuples in the fragment, providing data representing an output instance of the database in which detected tuples are replaced with selected candidate corrections.

Abstract: A computer implemented method for repairing records of a database, comprises determining a first set of records of the database which violate a functional dependency of the database, modifying records in the first set to make them consistent with the functional dependency to provide an output consistent database instance, determining a second set of records of the output consistent database instance comprising duplicate records, merging duplicate records in the second set in dependence on the functional dependencies of the records to provide a modified database instance.

Abstract: A computer implemented method for correcting records in a database comprising generating, using a processor, respective candidate replacement entries for multiple inconsistent records of the database, grouping the candidate replacement entries to provide multiple groups of related candidate updates for the database, ranking the groups according to a loss function to quantify database quality, receiving input for a selected group, sorting candidate replacement entries in the selected group, and applying updates from the selected group to the database to correct entries of the inconsistent records.

Abstract: A computer-implemented method comprising partitioning data representing an input instance of a database including multiple tuples into multiple fragments of tuples, detecting tuples which violate a data quality specification in respective ones of the fragments, selecting a data cleaning asset on the basis of characteristics of errors in detected tuples for a fragment and based on declared asset capabilities, assigning a selected data cleaning asset to the fragment, the selected data cleaning asset to provide a set of candidate corrections for the detected tuples in the fragment, providing data representing an output instance of the database in which detected tuples are replaced with selected candidate corrections.

Abstract: A computer implemented method for repairing records of a database, comprises determining a first set of records of the database which violate a functional dependency of the database, modifying records in the first set to make them consistent with the functional dependency to provide an output consistent database instance, determining a second set of records of the output consistent database instance comprising duplicate records, merging duplicate records in the second set in dependence on the functional dependencies of the records to provide a modified database instance.

Abstract: A computer implemented method for repairing records of a database, comprises determining a first set of records of the database which violate a functional dependency of the database, determining a second set of records of the database comprising duplicate records, computing a cost metric representing a measure for the cost of mutually dependently modifying records in the first and second sets, modifying records in the first and second sets on the basis of the cost metric to provide a modified database instance.