Cloud computing is baseline to invent next generation systems. As computer science is progressing by steps of cloud computing, same as requirements gathering, analysis in cloud computing getting more potential. The cloud computing enables services to fulfill requirements of cloud end-user, according to service level agreements. Data services over cloud also getting more potential especially real-time database systems are more critical to meet customer requirements over cloud. We will elaborate and present detailed analysis about requirements for real-time database systems over cloud, as well identify challenges and issues for RTDBs (real-time database systems) in cloud computing. There is need to ensure quality of service (QoS) as guaranty to meet requirements of RTDBs.