The Triple realm of database

It is hard to imagine that there are any applications that are irrelevant to the database. Even Microsoft's next-generation OS Vista uses its database to organize its new file system. It can be said that after years of development, the data has become the entire information process and the next stage of development of the most valuable resources, while the preservation and management of data resources of the database, its technology development and progress, has become the most worthy of concern and attention.

Guo Guowei has had a famous "triple realm" said, he will Yan Shu's "Butterfly Love Flower", Ouyang Xiu's "Butterfly Love Flower" and Sin "green Jade case" each of the three words, to tell the success of the Triple realm. And such a triple realm, it seems can also be borrowed to describe the development of database management technology. From the hierarchical database to the management relational database, and even the hybrid database supporting relational and XML at the same time, the database management technology has gone through a triple realm of constant innovation in the course of its development for nearly 40 years.

IMS: Escort the Apollo

Last night the West wind was green. Alone on the high-rise, looking at the end of the world road, this sentence used to describe the database management system before the emergence of data management can be said appropriate. When data processing or punched cards are carried out, the management of the information at that time is the physical storage and processing of the cards. The storage and management of data is extremely cumbersome and complex, and it simply cannot reflect efficiency. After IBM produced its first disk drive (Model 305 ramac) in 1956, it triggered a revolution in data management and was thus able to store data randomly.

Since then, the earliest version of the database, the Network database management system (DBMS), was successfully developed by GE in 1961 and its IDs (integrated Datastore, integrated data storage) are the world's first networked DBMS and the first DBMS. But it can only run on the General Electric Mainframe, and the database has only one file, all tables must be generated by hand-coded, has great limitations.

To this end, the IBM developed hierarchical database IMS (Information Management system, information management systems) has been greatly welcomed, become the most famous and most typical of the hierarchical database management system.

In 1966, IBM, in collaboration with its customers (Rockwell and Caterpillar), developed a new database to help NASA manage the cumbersome data of the ambitious Apollo program, and was completed by IBM engineers in 1968. The database was renamed "IMS" (Information Management system, information management systems) when it was released as an IBM product in 1969.

NASA continued to use the product in its space shuttle program in 1969, after NASA successfully launched Apollo 11th to make the first moon landing for humans. Until today, the database has always been useful, in today's Internet application connectivity, business intelligence applications such as the new role found.

RDBMS:IBM Open the New World

Although the hierarchical database has been a good solution to the problem of data centralization and sharing, it still lacks in data independence and abstraction level. Therefore, make the database management personnel rather "Shiriko end not regret, for the Iraqi people gaunt." ”

Fortunately, just in 1970, IBM researcher e.f.codd 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 a landmark milestone in the history of database systems. After continuous development and argumentation, finally make the more advantageous relational database becomes the mainstream of the market. Then, in 1974, Ray Boyce and Don Chamberlin of IBM presented the SQL language, which implemented all the operations of the database lifecycle and laid another milestone for the relational database.

In 1979, IBM completed the first DBMS to implement SQL. In the early 80 of the 20th century, IBM took advantage of the second phase of RDBMS and SQL technology to create a new database product named DB2, a database product with second-generation technologies. Over the years, DB2 has evolved from important mainframe products to products that run on a variety of server platforms. Especially in System 390, now called System Z, DB2 has become the core of distributed computing.

In spite of the constant competition of the database products of the same period manufacturer, DB2 is still widely used and praised in the high-end enterprise application market. After years of development and progress, nearly 500,000 DB2 data servers have been running on System z and on the Intel platform where Linux systems are installed.

IBM DB2 9: A mature master of optimization

With the development of informatization process and the need of enterprise and internal information exchange, XML, as a standardized data storage format, is facing a huge increase in data volume. In fact, every industry is implementing XML data standards, and 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 progressively implement SOA by exchanging data between different systems and applications and adapting to fast-changing environments.

"The crowd seeks him 1100 degrees, look back mo See, that person is, the lights are dim." The DB2 9 (code-named Viper), which combines the characteristics of relational and hierarchical databases, introduces another possible-hybrid database, which can support XML data very well, but also for other technologies including SQL, Support for tabular data structures and various DBMS features still exists.

Before that, file systems can handle simple tasks, but they perform poorly when they need to work on a large number of documents. Issues such as concurrency, recovery, security, and availability are becoming unmanageable. Although the business Relation database management system (DBMS) solves these problems, it is deficient in other aspects. DBMS typically simply provides two basic database design options-storing each XML document completely as a large object, or "tearing it apart" and spreading it across multiple columns in multiple tables. Not only does this not fully embody the hierarchical structure of XML, but also inefficient and inflexible.