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real time data base

Many real-time applications need to store large amounts of data and process these data for their successful op¬eration. Such storing requirements occur when a controlling system needs to maintain an uptodate state of the controlled system. A few examples of such systems include a network management system, an industrial control system, and an autopilot system. Whenever storing and processing large amounts of data is required, a database management system is used. The need for a database management system for storage and processing of large volumes of data and the basic issues in relational database management systems (RDBMS) have been profusely discussed in standard database literature such as [1, 2, 3] and we assume that the reader is already familiar with these issues. The focus of this chapter is real-time database management systems (RTDBMS) that are used in data intensive real-time applications, such as network management systems, industrial control systems, autopilot systems, etc.
As traditional database systems do, real-time database systems also serve as repositories of large volumes of data and provide efficient storage, retrieval, and manipulation of data. However, there are a few important differences between traditional and real-time databases.
The main differences between a conventional database and a real-time database lie in the temporal charac¬teristics of the stored data, timing constraints imposed on the database operations, and the performance goals.

We elaborate these issues in this chapter. It would become clear that these issues make design and development of a satisfactory real-time database application much more difficult and complicated compared to traditional database application.

This chapter has been organized as follows. We first briefly examine a few applications needing support of a real-time database. Next, we review some of the basic concepts in traditional database technique that are relevant to the discussions in this Chapter. Subsequently, we elaborate implications of the temporal characteristics of data in a real-time database. Finally, we discuss some concurrency control protocols that can be used in real-time databases.