Apache IoTDB
Deductive Database with Datalog, SQL, RA, TRC, DRC
With aguacate you get a better taste
A Database System for Metamodeling and Method Engineering
MySQL Proxy using Java NIO based on Sharding SQL, Calcite
Automated testing to find logic and performance bugs
World's first open source data quality & data preparation project
Data quality analysis, profiling, cleansing, duplicate detection +more
Java Editor For DataTables