In this chapter, spectrum management technologies based on a spectrum database are introduced. Statistical spectrum maps and spectrum databases are important components for understanding a spectrum environment that has locality due to geolocation, surrounding structures, frequency, and so on. The typical spectrum database provides spectrum information according to a radio propagation model for estimating the unused spectrum for spectrum sharing. However, the original geolocation spectrum database does not consider the site-specific environment because a statistical radio propagation model is used. Here, in order to improve the accuracy of the spectrum database, the measurement-based spectrum database is considered. The highly accurate spectrum database can improve spectrum-sharing performance and spectrum efficiency. Finally, a future spectrum management concept, called a smart spectrum, is introduced to open up the possibility for a new wireless world.