Study On Real-Time Data Model And The Design And Implementation Of A Real-Time SQL

The real-time data model (RTDM) is the core and foundation of the real-time database (RTDB). In recent years, the RTDB has been used widely. Now not many results have been reported for discussing the issue of the data model. So it has important meaning for carrying on and strengthening this research of data model.The being mutually related question of real-time data model and Real-Time SQL was chiefly discussed in this thesis. Firstly, we designed a Real-Time data model (TrssM) based on the requirement of the RTDB and the radar supervision system (Trss). The design thought of the TrssM is adding the notion of timing constraints to conventional data model. The RTDM comprises three parts: 1. Real-Time data object. 2. The operation in time relational algebra. 3. Timing constraints. It includes data temporal consistency constraints, timing constraints on execution and timing constraints on transaction.Secondly, we designed the real-time database operation language-TrssSQL for the Trss. The TrssSQL includes extensions that specify: temporal constraints on data, timing constraints on execution, bounds on use of system resources for predictability, and flexible transaction structure that relaxes traditional ACID transaction properties to better support real-time requirements.