Research And Implementation Of Key Technologies In PL/SQL Engine Of GKD-Base

With the wide application of computer in military, information become important in high-tech war environment. As the kernel of information system, Database Management System (DBMS) is charged with information storage and management and is playing more and more important role in information war. GKD-Base is a native Security Database Management System. Compared with commercial DBMS, GKD-Base has many limitations for lack of some important functions. It needs extending and upgrade. This project is intended to solve the key technique in GKD-Base's function extending.This paper focuses on the research and implementation of several key techniques in PL/SQL engine. Starting from the design of PL/SQL engine's architecture, this paper discusses the basic structure of compiler and executor. In the PL/SQL compiler, we designed a special symbols table, which used stack and array data structures. The structure of symbols table supports efficient symbols searching, and realizes the visibility of variables in nested PL/SQL block as well.Then, we discusses in detail the implementation techniques of the trigger mechanism, including the model of trigger in DBMS, triggering mechanism, cascade triggering, trigger termination analysis and so on. For implementing trigger, a method of tighten coupled with database core, data structures and algorithms are presented. Meanwhile, an efficient way of accessing database dictions, new tuple and old tuple of row-level trigger is proposed. For further enhancing the efficiency of trigger mechanism, we designed the triggers managerAt last, the parsing of Object Oriented mechanism is discussed. The parsing methods of package and record are described, which is similar to the parsing of Object Oriented mechanism. Based on this mechanism, we designed the objects manager. So the parsing of Object Oriented mechanism is implemented. The function overload and the class inherit brings the polymorphism problem, to which a solution is put forward.All the technologies discussed in this paper have been applied in GKD-PL/SQL engine. Now, the engine can run stably. We have compared it with the PL/SQL engine of Oracle. It can be concluded that the GKD-PL/SQL engine is compatible with that of Oracle.