Abstract: Now keyword search over relational database is becoming a hot research topic in both database and IR area. There are two kinds of popular keyword search systems, while neither of them can give accurate results with high speed. The on-line system can obtain the latest search results while the search speed is low; The off-line system speeds the query processing by means of preprocessing, but the disadvantage lies in expensive cost needed to preprocess again once the database is updated. An incremental update solution is designed based on an off-line system DIRECTOR to synchronize the updating of data graph with the database. It improves the real-time characteristic of the querying without decreasing its effectiveness. Another contribution of this research is that a universal pre-processing module is used to facilitate pre-processing even with limited knowledge of database schema.