In our research, we deal with all aspects of data management. We are attracted by applications that are heavily based on data but cannot leverage current systems due to the rich set of queries they need. The focus of our research is on queries over complex objects and massive data collections, data cleaning and integration, indexing techniques, query processing and optimization, distributed data management, and numerical computations in databases. Our research is triggered by problems that arise in concrete applications, for example, process mining, digital humanities, or cognitive neuroscience. The results of our research are new algorithms with performance guarantees, which are implemented and evaluated on the motivating application.