Research And Implementation Of Transaction Processing Technology In Native XML Database XSQS

With XML becoming the standard for data representation and exchange over the Internet, the need to exchange and process XML data over the Internet is dramatically increasing. Therefore, the research on the efficient storage management of XML data is becoming more and more important. The support from traditional database system for XML has a native limit to process logical structure and data integrity of this semi-structured data type, but the Native XML database to manager the XML data has the advantage that the traditional database system doesn't, and in recent years it has got researchers' attention. But, the existing native XML database products are also far from perfect in a view of database system. One of native XML database's biggest weaknesses is the support for transaction processing and concurrency control techniques. At the present, the XML transaction processing is still in the initial stage.Transaction is one of the core concepts in modern database theory, and concurrency control technology is the major component of transaction management.In the review of existing concurrency control protocol for XML, this paper proposes a transaction processing framework for the Native XML database prototype XSQS (XML Storage and Query System).It is designed for the unique characteristics of XSQS.Firstly, the XSQS update function is realized basicly in this paper. And then the transaction processing model for XSQS is proposed based on the update function, and by comparing the concurrency control mechanism strategy, a concurrency control protocol is used for XSQS.It is a strict two-phase locking protocol to achieve the concurrency implementation to meet characteristics of XSQS.Then, the two granularity locks, document-lock and path-lock, are proposed to meet the actual needs, by analyzing from the perspective of the lock and the data concurrence. In this moduel, the concurrency implementation is realized by thread pool, and control of resources in the lock mechanism is to ensure the atomicity, consistency, durability and isolation of transaction.Finally, the paper discusses how to design and implement the transaction processing module on the database prototype, XSQS. In the design of transaction module, the algorithms of locked and unlocked is analyzed for concurrency control, and the function for multi-transaction handling of concurrency control is proved by experiment-test of the transaction processing module. The preliminary result shows, that the two-phase locking protocol can do well for supporting the transaction concurrency in XSQS.