Research And Implementation Of Index And Concurrency Controls In NHSecure

With the rapid development of information technology, applications of the database have obtained an enormous popularization as core software to store and process the data; it creates and manages massive data more effectively and safely. Each technology of implementations of the database management system will become the important research direction in database domain. This paper studies the theories and implementations of the index and concurrent control in DBMS, and it designs and implements the index mechanism sub-system and concurrent control sub-system of NHSecure. As follows are details:⑴It introduces some traditional index mechanisms and concurrence control mechanism of DBMS, and analyzes their characteristics.⑵It complements the transformation from the SQL to the structure of operation information that the system obtains actually, using the syntax analysis and the lexical analysis. And based on B+ tree, it proposes the BF tree, an extensible and controllable index structure. The BF tree will be used for extending the index of NHSecure,and raising memory utilization ratio.⑶It proposes a down-to-up index construction to realize the efficiency, according separating the data file form index document. It proposes an efficient node insertion and delete arithmetic using the adjust factor and the method of adjusting the brother nodes.⑷It designs the B/S pattern of NHSecure for multi-user and the operation pattern in different platform.⑸It discusses the types and granularities of lock of concurrent mechanism, and implements the concurrent control of tuple-level according to the Strict-2PL.⑹It designs the module for auto-upgrading the lock granularity, and implements the types transformation from low-granularity to high-granularity under some conditions, using the intelligent upgrading arithmetic.