The present invention provides a method for transforming a concept-based query into SQL query statements, comprising the steps of: transforming inputted concept-based queries into logic rules; checking validity of the logic rules; optimizing the valid logic rules; and translating the logic rules into SQL query statements in accordance with the optimization result. The present invention further provides corresponding transformation engine, database query system and computer program product. The present invention facilitates people to use more descriptive query language to query data stored in relational database. Furthermore, the present invention can automatically generate the correct and efficient SQL query statements so that people's efforts to deal with complex data model are saved significantly.