Composition of database system
Source: Shangpin China |
Type: website encyclopedia |
Time: June 16, 2014
Database system is generally composed of database, database management system (and its development tools), application system, database administrator and user. below Website production company Shangpin China introduces the contents of these parts respectively. 1. Hardware platform and database Due to the large amount of data in the database system and the large scale of DBMS due to its rich functions, the entire database system requires high hardware resources. These requirements are: (1) There should be enough memory to store the operating system, core modules of DBMS, data buffer and application programs. (2) There are enough large disks and other direct access devices to store the database, and there are enough tapes (or computer floppy disks) for data backup. (3) The system is required to have high channel capacity to improve data transmission rate 2. Software The software of database system mainly includes: (1) DBMS, DBMS is the software configured for the establishment, use and maintenance of database. (2) Operating system supporting DBMS operation. (3) It has a high-level language and its compilation system that interface with the database, which is convenient for developing application programs. (4) Application development tool with DBMS as the core. Application development tools are various software tools provided by the system for application developers and end users, such as efficient and multi-functional application generators, the fourth generation languages, etc. They provide a good environment for the development and application of database systems. (5) A database application system developed for a specific application environment. 3. Personnel The personnel who develop, manage and use database systems mainly include database administrators (DBAs), system analysts and database designers, application programmers and end users. Different personnel are involved in different data abstraction levels and have different data views. Their respective responsibilities are as follows. 1) Database administrator In the database system environment, there are two types of shared resources: one is the database; The other is database management system software. Therefore, a special management organization is needed to supervise and manage the database system. The DBA is a member of this organization, responsible for the overall management and control of the database system. Specific responsibilities include: (1) Determine the content and structure of information in the database The DBA should participate in the decision-making of what information should be stored in the database. Therefore, DBA must participate in the whole process of database design, and work closely with users, application programmers and system analysts to negotiate and do a good job in database design. (2) Determine the storage structure and access strategy of the database DBA should integrate the application requirements of each user, and jointly determine the data storage structure and access strategy with the database designer to obtain higher access efficiency and storage space utilization. (3) Defining data security requirements and integrity constraints DBA's important responsibility is to ensure the security and integrity of the database. Therefore, DBA is responsible for determining each user's access rights to the database, data confidentiality level and integrity constraints. (4) Use and operation of monitoring database Another important responsibility of the DBA is to monitor the operation of the database system and deal with problems in the operation process in a timely manner. For example, when various faults occur in the system, the database will be damaged to varying degrees. The DBA must restore the database to the correct state in the shortest time, and try not to affect or less affect the normal operation of other parts of the computer system. To this end, DBAs need to define and implement appropriate backup and recovery strategies, such as periodic dump of data and maintenance of log files. This aspect will be further discussed below. (5) Improvement, reorganization and reconstruction of database DBA is also responsible for monitoring the space utilization rate, processing efficiency and other performance indicators of the system during system operation, recording and statistical analysis of the operation, and constantly improving the database design based on work practice and actual application environment. Many database products provide utilities to monitor and analyze the database operation. DBAs can use these utilities to complete this work. In addition, during data operation, a large amount of data is constantly inserted, deleted and modified, which will affect the performance of the system for a long time. Therefore, DBA should reorganize the database regularly to improve the system performance. When the user's demand increases and changes, the DBA also needs to carry out a major transformation of the database, including the modification of part of the design, that is, the reconstruction of the database. 2) System analysts and database designers The system analyst is responsible for the requirement analysis and specification of the application system, and should combine with the user and DBA to determine the hardware and software configuration of the system, and participate in the outline design of the database system. The database designer is responsible for the determination of the data in your database and the design of the database models at all levels. The database designer must participate in the user demand survey and system analysis, and then carry out the database design. In many cases, database designers are database administrators. 3) Application programmer The application programmer is responsible for designing and writing the program module of the application system, and debugging and installing it. 4) Users The user here refers to the end user. The end user uses the database through the user interface of the application system. Common interface modes include browser, menu drive, table operation, graphic display, report writing, etc. End users can be divided into the following three categories: (1) Accidental user. These users do not often access the database, but they often need different database information each time they access the database. These users are generally senior and middle managers of enterprises or organizations. (2) Simple users. Most end users of the database are simple users, whose main job is to query and update the database. Generally, the database is accessed through an application program designed by the application programmer and with a friendly interface. Bank staff, airline ticket reservation staff, hotel front desk attendants, etc. are all such users. (3) Complex users. Complex users include engineers, scientists, economists, scientific and technological workers, etc. People with high science and technology background. Such users are generally familiar with various functions of the database management system, can access the database directly using the database language, and even can write their own applications based on the API of the database management system.
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