The main features of this stage can be summarized as follows:
* There is no software supporting data management in the computer.
* Data organization is application-oriented, and data cannot be shared and copied.
* The logical structure and physical structure of data should be specified in the program, and the data and program are not independent.
* Data processing method-batch processing. The main sign of this stage is that the computer has the software to manage the database-operating system (file management).
From the mid-1950s to the mid-1960s, the appearance of computer mass storage devices (such as hard disks) promoted the development of software technology, and the appearance of operating system marked a new stage of data management. In the file system stage, data is stored in external memory in units of files and managed by the operating system. The operating system provides a friendly interface for users to use files. The logical structure of the file is decoupled from the physical structure, and the program is separated from the data, which makes the data and the program have certain independence. User's programs and data can be stored in external memory respectively, and each application can enjoy a set of data, thus realizing data sharing in units of files.
However, because the data organization is still program-oriented, there is a lot of data redundancy. Moreover, the logical structure of data is not easy to modify and expand, and every slight change in the logical structure of data will affect the application. Because files are independent of each other, they cannot reflect the relationship between things in the real world, and the operating system is not responsible for maintaining the contact information between files. If there is a content connection between files, it can only be handled by the application. After the 1960s, with the wide application of computers in the field of data management, people put forward higher requirements for data management technology: they want to organize data for enterprises or departments, reduce data redundancy, provide higher data enjoyment, and require higher independence of programs and data. When the logical structure of data changes, it does not involve the physical structure of data, nor does it affect the application, thus reducing the cost of application development and maintenance. Database technology is developed on the basis of such application requirements.
Database technology has the following characteristics:
* For enterprises or departments, organize data with data as the center to form a comprehensive database of all applications.
* Use some kind of data model. The data model should not only describe the characteristics of the data itself, but also describe the relationship between the data.
* Small data redundancy, easy to modify and expand. Different applications get the required data from the database according to the processing requirements, which reduces the repeated storage of data and is convenient for adding new data structures and maintaining the consistency of data.
* The program and data are highly independent.
* With a good user interface, users can easily develop and use databases.
* Unified management and control of data, providing data security, integrity and concurrency control.
The development from file system to database system is a milestone in the information field. In the file system stage, the central problem people pay attention to in information processing is the design of system functions, so program design is dominant; In the database mode, data begins to occupy the central position, and the design of data structure becomes the first concern of information system, while the application program is designed based on the established data structure. Chronicle of events
195 1: Univac system uses magnetic tape and punched cards as data storage.
1956: IBM introduced the disk drive for the first time in its 305 RAMAC.
196 1: Charles buckman of General Electric Company developed the first database management system-IDS.
1969: E.F. Codd invented the relational database.
1973: Cullinane Company, led by John J.Cullinane, developed a database IDMS based on network model for IBM mainframe.
1976: Honeywell introduced the first commercial relational database product, Multics relational data storage.
1979: Oracle launched the first commercial SQL relational database management system.
1983: IBM introduced DB2 database products.
1985: proctor &; The first business intelligence system designed by Gamble system came into being.
199 1: W.H. "Bill "published" Building a Data Warehouse "on mon. With the continuous expansion of information management content, various data models (hierarchical model, grid model, relational model, object-oriented model, semi-structured model, etc. ) has emerged, and new technologies (data flow, Web data management, data mining, etc. ) have emerged. Every few years, some international senior database experts get together to discuss the current situation, existing problems and new technology focus that needs to be paid attention to in the future. Similar reports in the past include:1989 Future direction of DBMS research-Laguna beach participants; 1990 database system: achievements and opportunities; 199 1 w. h. Inmon's Building a Data Warehouse; 1995 database.