Information Sharing Platform Based On DB2 PureXML

With the development of network technology, more and more different hardware, multiple operating systems, various programming languages and a variety of communication protocols come out, which led some heterogeneous problems in the data source hardware equipment, running platform, implementation language, communication protocols and other aspects. However there is no uniform standards with each data source systems, and this often makes developers and end users faced multiple distributed heterogeneous system.In the data integration technology, PureXML has obvious advantages in data storage, index and query. XML technology makes it possible that a variety of heterogeneous database be described with the standardization of information, and it gradually becomes information fusion standards.XML is an extensible markup language and the self-description feature makes the XML itself very suitable for data exchange between heterogeneous databases. There is no pre-specified data structures defined as the premise of the exchange. XML has a strong openness and good growth. XML has the following significant features. The first one is the design of self-description which means data can be described itself. XML is described by a number of tags to improve the readability and easy reading. Second, the hierarchical structure of the data organization is a tree and the data level can be reflected by the level of the structure. The relationship between the data is clearly visible. XML data has been a standard with the technology becoming matures. It will be a inevitable trend that information technology platform built on XML.The mainstream large database systems mostly are XML-based integration. Pure XML is a "node-level" grain storage XML, and it supports XML column index to create a specific path and can create connections across the document index that can access the document in the shortest possible time node. And it can be mixed in the same statement using SQL and XQuery, which makes the search more powerful.DB2 Pure Xml functional components allow well-formed XML documents stored in a type of table columns in the form of a hierarchical structure of XML data. Through the XML data stored in the XML column, data can maintain its native hierarchical structure,instead of storing it as text or mapped to other data models. Because Pure Xml data storage has been fully integrated,so we can use existing DB2 data server functionality to access and manage storage of XML data. The XML data stored to the machine's hierarchical structure to allow for storage retrieval and updating of XML more efficient. XQuery, SQL, or a combination of the above can be used to query or update data in XML,return SQL functions (often referred to as SQL / XML functions) of XML data or XML-independent variable (independent variable) also can constract or release data of XM structure according to value searched from database.Smallest unit of PureXML storage is node and is not a document, Therefore, in some database of XML, physical storage layer of the primary storage unit is the node, not document. There is a node in each page of database, the addition of the other nodes are from the same or different documents. In these nodes, each node not only link the father node, also link to their child nodes. This makes the efficiency of browsing improved. Some applications manage millions of XML documents, and such applications are not uncommon. Therefore, to provide data index to improve query performance. The importance of the index in the database will not repeat here, DB2 support the establishment of a specific index of the path in XML columns, so the verb (predicate) often used is generally attribute (attribute) and some elements (elements), documents and preparation of cross-linked index is allowed, this is the new XML indexing features. XML pattern expression can effectively evaluate new XML index, this make XML document query become more efficient.This item comes from Changchun Science and Technology Bureau, which has four remote database, including Changchun Science and Technology Library, results sharing platform libraries, large instrument library, as well as experts database. In order to achieve the blending of scientific and technological laboratory results, technological development, the experts used by the existing results, the instruments, the development of fusion status and the existing technology of expert information, research and information fusion, we establish this system. The fundamental purpose is that to allow the user to customize a new database which will meet their needs through the system based on the original database, the existing data type (data type), database definition and the existing data, and at the same time , keep on with the original database to maintain data synchronization. After the application of pure XML technology, we extracted the information that associated to the system information table and store it to a form of XML in XML documents, then represent it out of a tree structure in accordance with the related items. After originally extracted from the relational database data, it will be stored in XML documents and transmissed, and then decomposited in the specified goal database into relational data, extracted from the relational data to build the component-level data object, which will be used to demonstrate the application. The decomposited one will still be performed in form of XML .The application form will be completed by indicating XQuery through the XML documents. Through detailed analysis of the author and the structure given in the article, the specific is implemented.Pure XML builds the interaction between the models from the database engine (but at the same time still maintaining the independence of the data), providing the external personal use through the public interface, and the internal concrete implementations are very flexible by using the number of DB2, the existing comcept and original unique logic. On deeper level, the organic integration of the two models greatly enhanced the data storage capacity of non-structure data of DB2, which is also an important component idea of the large enterprise data management. It can be said that the emergence of Pure Xml technology conforms to the trend of the data information industry, Pure Xml will lead database logic and computing to a higher position.