Data is eating the world. Systems for storing and processing data, such as Database Management Systems (DBMSs), are thus pivotal for our computing infrastructure. It is critical that they function correctly — incorrectly computed results (e.g., by omitting a row) can cause serious loss or damage. Despite their importance, finding such logic bugs in production DBMSs is a longstanding challenge. This talk presents novel, general approaches to effectively detecting logic bugs in DBMSs by tackling the test oracle problem, i.e., deciding whether the returned result for a query is correct. These approaches were realized as the SQLancer open-source tool, which was evaluated on widely-used, production-quality DBMSs, such as SQLite, MySQL, and PostgreSQL. To date, SQLancer has found over 450 unique previously unknown bugs in these systems, most of which have been fixed by the developers. This body of work has provided solid methodological and technical bases for effectively testing DBMSs and has already been widely adopted by industry. Many reliability challenges remain, not only for DBMSs, but also for other data-centric systems. The heterogeneous landscape in this space provides an exciting, fertile ground for new, practically relevant research for improving the reliability and performance of our society’s data processing infrastructure.