The three carriages ensure the connectivity of Oracle Networks

Oracle databases are typical representatives of network databases. You can access the Oracle database over the network. Oracle Database provides a variety of network interconnection solutions, including the structure and driver, its network communication protocol structure is similar to the OSI-RM, but has its own layered mechanism. That is to say, the Oracle network is based on the computer network, oracle implements data sharing, data integrity control, secure data transmission, and cross-operating system platform through the network (it can run on both Linux and Microsoft operating system platforms) and data operations between multiple hardware platforms.

So what guarantees the connectivity of the Oracle network? To put it simply, the three carriages, Global Database Name, listener and Network Service name, ensure the connectivity of the Oracle network.

The first carriage: Global Database Name.

Before talking about the global database name, I 'd like to talk about the domain name www.britepic.org. The domain name on the internet is equivalent to the house number in our real life. It can guide us to the site we want to visit in a complicated online world. From the domain name www.britepic.org, it is composed of several different parts. These different parts have upper and lower hierarchies. Among them, the last. CN is the first layer of the domain name,. COM is the second layer of the domain name, And. Ctocio is the real domain name, on the third layer, and so on. So far, we can see that the domain name level from the back to the front is similar to a inverted tree structure. The first-level. CN Domain Name is a top-level geographic domain name. Under these geographic top-level domain names, you can also define the second-level domain names as needed. For example, top-level domain names in China. CN has been set up again. COM ,. NET ,. ORG ,. GOV ,. EDU, and the letter representatives of various administrative divisions in China, such. BJ represents Beijing ,. SH represents Shanghai and so on. Therefore, when accessing a website, you only need to enter the domain name (www.britepic.org) to open the corresponding website without entering an IP address that is hard to remember.

The Oracle database system is a large-scale distributed database system. Sometimes, for performance and other considerations, you often need to deploy multiple database systems in multiple places of the enterprise, which constitutes an Oracle distributed network environment. To ensure the uniqueness of each database name, the Oracle database system uses the domain name naming rules to name databases distributed in different regions. That is, the global name of a database is composed of the database name and the domain name of the database. Assume that an enterprise has three offices in Ningbo, Hangzhou, and Zhoushan, and three Oracle databases are deployed respectively, with Hangzhou as the headquarters. The structure is as follows:

According to the global database naming rules, the Database Name of Hangzhou company is ORAL. dtm ningbo company. The database name of Zhoushan company is ORAL. NINGBO. DTM, and the database name of Zhoushan company is ORAL. ZHOUZHAN. DTM. In this case, it is very convenient for the application to connect to the databases of different departments. You can specify the data objects to be accessed by using the global database name. You can connect to the database you want to connect to by simple modification. In addition, you can configure a default domain in the network environment, so that you do not need to specify a domain name to access the database objects in the default domain.

Using the global database name can provide two benefits. First, it is easy to expand the database. For example, an enterprise may only use one database to process the business. However, when an enterprise grows, a database may not meet performance requirements. Or, you need to deploy a distributed database environment for enterprise merging and other reasons. In this case, you can expand the database environment without changing the existing database. Second, facilitate database connection. When users change between different databases, It is very convenient to use the global database name.

Therefore, the author suggests that the database administrator should be able to define the name according to the global database naming rules even if the enterprise currently only has one Oracle database. In order to facilitate subsequent database expansion, it also facilitates the daily maintenance of the database administrator.

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