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

In this issue, the editor will bring you about the characteristics of the distributed database system. The article is rich in content and analyzed and described from a professional point of view. I hope you can get something after reading this article.

The operating environment of this tutorial: windows7 system, Dell G3 computer.

Distributed database system (DDBS) includes distributed database management system (DDBMS) and distributed database (DDB). In a distributed database system, an application program can transparently operate the database. The data in the database is stored in different local databases, managed by different DBMS, run on different machines, supported by different operating systems, and connected by different communication networks.

Characteristics of distributed database system

1. Independent transparency (distributed transparency)

Data independence is one of the main goals of database methods. Distribution transparency means that users do not have to care about the logical partition of data, the details of the physical location distribution of data, the consistency of duplicate copies (redundant data), and which data model is supported by the database on the local site. The advantage of distribution transparency is obvious. with distribution transparency, users' applications can be written as if the data were not distributed. there is no need to rewrite the application when data is moved from one site to another. When adding duplicate copies of some data, it is not necessary to rewrite the application, the information of data distribution is stored in the data dictionary, and the user's access request to non-local data is interpreted, transformed and transmitted by the system according to the data dictionary.

2. Centralized node combination

Database is the resources shared by users in the centralized database, in order to ensure the security and integrity of the database, the control of the shared database is centralized, and there is a DBA responsible for supervising and maintaining the normal operation of the system. In a distributed database, there are two levels of data sharing:

The first is local sharing, that is, the shared data of users on the local site are stored in the local database, which are commonly used by users of this site.

The other is global sharing, that is, the data that can be shared by users of other sites in the network are also stored in each site of the distributed database to support the global application in the system.

3. Copy transparency

Users do not have to care about the replication of the database at each node in the network, and the updates of the replicated data are automatically completed by the system. In the distributed database system, the data of one site can be copied to another site for storage, and the application program can use the copied data to complete the distributed operation locally to avoid transmitting data through the network. it improves the operation and query efficiency of the system. However, the update operation of replicated data will involve the update of all replicated data.

4. Easy scalability

In most network environments, a single database server will eventually be unsatisfactory for use. If the server software supports transparent horizontal scaling, multiple servers can be added to further distribute data and share processing tasks.

These are the characteristics of the distributed database system shared by the editor. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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