In recent years, encrypted databases have emerged as a promising direction that provides data confidentiality without sacrificing functionality: queries are executed on encrypted data. However, existing practical proposals rely on a set of weak encryption schemes that have been shown to leak sensitive data. We present Arx, the first practical and functionally rich database system that encrypts the data only with strong, semantically secure encryption schemes. We show that Arx supports real applications such as ShareLatex and a health data cloud provider, and that its performance overhead is modest.