Section: New Results

Data Transformation Management

With the increasing complexity of data processing queries, for instance in applications such as relational data analysis or integration of Web data (e.g., XML or RDF) comes the need to better manage complex data transformations. This includes systematically verifying, maintaining, and testing the transformations an application relies on. In this context, Oak has focused on verifying the semantic correctness of a declarative program that specifies a data transformation query, e.g., an SQL query. To this end, we have investigated how to leverage data provenance (the information of the origin of data and the query operators) for query debugging. More specifically, we developed and implemented novel algorithms to explain why data is missing from the result of a relational query. As opposed to our previous work, which produced explanations based on the available source data, our new algorithms return explanations based on query operators [31] or both [26] .