DB2 9 data server development 3

The db2 tutorial is: DB2 9 data server development 3 workshop.

It is hard to imagine that another application is irrelevant to the database. Even Microsoft's next-generation operating system, Vista, uses its database to organize its new file system. It can be said that, after years of development, data has become the most valuable resource for the whole informatization process and the development of the next stage, and the database for storing and managing data resources, the development and progress of its technology, it has become the most noteworthy and important issue. From hierarchical databases to management of relational databases, and even the current hybrid database DB2 9 that supports both relational and XML, database management technology has been developing for nearly 40 years, it has roughly gone through the above three stages.
IMS: an early hierarchical Database

In the past, data management in the database management system was very primitive and simple. When data processing relies on punched cards, data management only physically stores and processes cards. The storage and management of data is extremely troublesome and complex, and cannot reflect the efficiency at all. After IBM produced the first disk drive (Model 1956 RAMAC) in 305, the data management revolution was triggered and data was stored randomly. Since then, the earliest version of the database, namely the network database management system (DBMS), was developed successfully by GE in 1961. Its IDS (Integrated DataStore, Integrated data storage) is the world's first mesh DBMS and the first DBMS. However, it can only run on a General Electric host, and the database has only one file. All Tables must be generated by manual encoding, which has great limitations. To this end, the Information Management System (IMS) developed by IBM has been greatly welcomed and has become the most famous and typical hierarchical database Management System.

In 1966, IBM worked with its clients (Rockville North America and caterpillar) to develop new databases to help NASA manage tedious information in the ambitious Apollo program, IBM engineers completed this operation in 1968. In 1969, the database was renamed "IMS (Information Management System)" when it was released as an IBM product ). In 1969, after NASA successfully launched the Apollo 11 program to reach the first moon landing for humans, NASA continued to use the product in its space shuttle program. Until today, the database has been useful and has found a new role in today's Internet application connection, business intelligence and other applications.

RDBMS: the emergence of relational databases

Although the hierarchical database can effectively solve the problem of data integration and sharing, it still lacks data independence and abstraction level. Fortunately, in 1970, IBM researcher E. F. Codd proposed the concept of the relational model, thus laying the theoretical foundation of the relational model. His paper "A Relational Model of Data for Large Shared Data Banks" is also considered an epoch milestone in the history of database systems. After continuous development and demonstration, the more advantageous relational databases became the mainstream in the market. Later, in 1974, Ray Boyce and Don Chamberlin of IBM proposed the SQL language, which realized all the operations in the database lifecycle and laid another milestone for relational databases.

In 1979, IBM completed the first DBMS to implement SQL. In the early 1980s S, IBM used the second-stage technology of RDBMS and SQL to create a new database product and named it DB2, that is, database products with second-generation technologies. In the past few years, DB2 has evolved from an important mainframe product to a product that can run on various server platforms. Especially in System 390 (System z), DB2 has become the core of distributed computing.

Despite the constant competition of database products from manufacturers in the same period, DB2 is still widely used and praised in the high-end enterprise application market. After years of development and progress, nearly 0.5 million DB2 data servers have been running on System z and Intel Platform with Linux systems installed.

IBM DB2 9: the first hybrid Data Server

With the development of information technology and the need for information exchange between and within enterprises, XML, as a standardized data storage format, is facing a huge increase in data volume. In fact, XML data standards are being implemented in every industry. The new Microsoft Office software will also store documents in XML format. In addition, more and more companies are turning to XML technology to help them gradually implement SOA by exchanging data between different systems and applications and adapting to rapidly changing environments. DB2 9 (codenamed Viper), which combines the characteristics of relational databases and hierarchical databases, introduces another possibility-hybrid databases, which can support XML data very well, other technologies, including SQL, table data structures, and various DBMS features, are also supported.

Previously, file systems were able to handle simple tasks, but they were not doing well when they needed to process a large number of documents. Concurrency, recovery, security, availability, and other issues become difficult to manage. Although the commercial relational database management system (DBMS) solves these problems, it is lacking in other aspects. DBMS generally only provides two basic database design options-to store Each XML document completely as a large object or to "tear it apart ", distributed and stored in multiple columns of multiple tables. In this way, the XML Hierarchy cannot be fully reflected, and the efficiency is low and not flexible enough.

In addition, pure xml dbms introduces a new environment in IT infrastructure, but such an environment has not yet been tested, its integration capabilities, required personnel skills, and future vitality are also unknown. Therefore, it is necessary to find a system that can efficiently share, search, and manage a large number of XML documents and messages in order to help enterprises reduce the time and effort required to store and use XML data, in order to reduce application development costs and improve business flexibility. Hybrid database DB2 9 meets this need. With DB2 9, you can use the same database object to manage "traditional" SQL data and XML documents at the same time, or even write a query to search and process both data forms at the same time.

DB2 is the industry's first and only relational data that can use industry-standard interfaces to manage pureXML databases. It has unique innovations in three fields: XML data management, data compression, and SAP optimization. Among them, the most important feature is XML data management, which uses IBM's "pureXML" solution to manage data stored in XML format.

This means that DB2 9 can provide the "original" Storage of XML data without converting the data into row and column formats, and does not need to store it as a large object. To achieve this feature, IBM has extended DB2 so that DB2 9 includes the following new technologies:

The new storage technology enables efficient management of the hierarchies inherent in XML documents.

The new indexing technology improves the search speed between XML documents and internal documents.

New Query Language Support (for XQuery ),

New graphical Query Builder (for XQuery) and new query optimization technology.

Test the XML data capability based on the mode provided by the user.

New management functions, including the expansion of key database tools.

Integration with popular application programming interfaces (APIS.

With the application of compression technology, DB2 9 can save customers 40 to in actual tests ~ 80% of storage requirements, while maintaining or even improving application performance. Based on the revolutionary innovation and performance of DB2 9, SAP also selects DB2 9 as the data server for Small and Medium customers who use mySAP commercial applications.