In this paper, we propose a visual interface for manipulating relational databases (RDBs). This interface, unlike structured query language (SQL), describes queries in a procedural language with graphs. This helps inexperienced users to interact with RDBs, and also helps experienced users to express nontrivial queries properly. It also supports SQL-DML (SELECT, INSERT, UPDATE, DELETE), ensuring there is no missing functionality in database manipulation. It also introduces the system architecture and algorithms for the inter-conversion between SQL and the Visual Query Interface. This architecture can support various RDBMSs.