Shulou(Shulou.com)06/01 Report--

The composition of the database system is shown in the following figure.

1) hardware

The hardware of the database system includes the host computer, keyboard, monitor and peripherals (such as printers, optical drives, tape drives, etc.). Due to the large amount of data stored and processed by the general database system, coupled with the rich functional software of DBMS, the storage space occupied by itself is very large, so the whole database system puts forward higher requirements for hardware resources.

These requirements are:

① has enough memory to hold the operating system, DBMS core modules, data buffers, and applications

② has enough direct access devices to store data (such as disks) and enough storage devices to back up data.

③ requires the computer to have high data transmission ability to improve the data transmission rate.

2) Software

In addition to the database management system, the software of the database system also includes various high-level language processors (compilers or interpreters), application development tools and specific application software of the operating system. Application development tools include efficient and multi-functional software tools such as application generator and the fourth generation language, such as report generation system, table software, graphic editing system and so on. They provide strong support for the application developers and end users of the database system. Specific application software refers to database application software developed for specific users, such as various management software based on database, management information system (MIS), decision support system (DSS), office automation (OA) and so on.

3) data

Data is the basic component of the database, a representation of the things that exist in the objective world, and the operating object of database users. Data is not only the database system, but also the real wealth of the enterprise or organization. The data should be collected according to the requirements and stored in the human database in a structured way. Due to the diversity of data types, the ways of data collection and storage will be different. Data as a resource is the most stable component in the database system, that is, the hardware may be updated, and even the software can be updated, but as long as the nature of the enterprise or organization does not change, data will be a wealth that can be used for a long time. The data in the database has the characteristics of collection, sharing, minimum redundancy and being able to serve a variety of applications as mentioned earlier.

4) user

Database users are the main body to manage, develop and use the database. According to the differences of work tasks, database users can usually be divided into three types: end users, application programmers and database administrators.

(1) end user

End users use the terminal command language provided by the database system, or dialogue methods such as menu driver, table driver, graphic display and report generation to access and apply the data in the database. Such personnel are managers at all levels who are not proficient in computer and programming, but must receive the necessary training in database applications.

(2) Application programmer

Application programmers are the people responsible for designing and compiling applications. They usually use C language, database language, or 4GL (fourth generation language) to design and write applications for end users to use. Application programmers not only require high technical expertise, but also have deep qualifications, be familiar with the nature and use of all the data in the department, and have the ability of system programmers and system analysts.

Its specific duties are as follows:

① determines the content and structure of the database

② determines the storage structure and access strategy of the database, so that the storage space utilization and access efficiency of data are better.

③ defines security requirements and integrity constraints for data

④ designs and compiles all kinds of powerful applications according to the needs of end users.

For application programmers, there are two important tools that are necessary, one is a series of utilities (DBMS assembly, reorganization log, recovery, statistics, etc.), and the other is a data dictionary (storing database structure definition, record type, field definition, etc.). When the database system is established, DBA and the system analyst must also be responsible for the requirement analysis and specification of the application system, determine the software and hardware configuration of the system and participate in the design of the database.

(3) Database administrator

Database administrator (data basead ministrator,DBA) refers to the person who is fully responsible for the daily management, maintenance and operation of the database system. DBA is between the end user and the application programmer, which is the key to the normal operation of the database system. Large database systems need to set up a special management office. Its duty is to supervise and control the use and operation of the database, implement the maintenance, improvement and reorganization of the database system, and carry out information socialization service.

For database systems of different sizes, the staffing of users is different. Only large database systems are equipped with application programmers and database administrators. The applied microcomputer database system is relatively simple, and its users usually have the functions of both the end user and the database administrator, but they should also have the ability of the application programmer if necessary.

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