In this paper, we propose four architectures for intrusion-tolerant database systems. While traditional secure database systems rely on prevention controls, an intrusion-tolerant database system can operate through attacks in such a way that the system can continue delivering essential services in the face of attacks. With a focus on attacks by malicious transactions, Architecture I can detect intrusions, and locate and repair the damage caused by the intrusions. Architecture II enhances Architecture I with the ability to isolate attacks so that the database can be immunized from the damage caused by a lot of attacks. Architecture III enhances Architecture I with the ability to dynamically contain the damage in such a way that no damage will leak out during the attack recovery process. Architecture IV enhances Architectures II and III with the ability to adapt the intrusion-tolerance controls to the changing environment so that a stabilized level of trustworthiness can be maintained. Architecture V enhances Architecture IV with the ability to deliver differential, quantitative QoIA services to customers who have subscribed for these services even in the face of attacks.