Shulou(Shulou.com)06/02 Report--

The main content of this article is "how to solve the Java multi-database system", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to solve the Java multi-database system.

There are many ways to construct a database system, in which we examine the differences of these multi-databases, which are mainly manifested in the following aspects of heterogeneity:

The main contents are as follows: (1) the heterogeneity of database logical data model: there are five kinds of databases: hierarchical, mesh, relational, object-relational and object.

(2) the heterogeneity of the physical data model of the database: the physical data model reflects the storage structure of the database, such as physical block, pointer, index and so on. Even if the logical data model is the same, such as ORACLE, SYBASE, DB2 and so on, the physical data model of the relational database is also different.

(3) the heterogeneity of operating system: UNIX, WINDOWS series, MacOS, OS/2, DOS and so on.

(4) the heterogeneity of computer platforms: from giant, large, medium and small computers to workstations, microcomputers and handsets.

(5) the heterogeneity of the network: LAN, WAN, Ethernet bus structure and token ring structure, etc.

Some of these heterogeneity are caused by the history of databases, such as hierarchical and mesh databases; some are caused by different database management systems developed by different database developers; some are caused by different computer operating systems; and some are due to network structures and computer platforms. For these differences, at present, we think that we should focus on different operating systems and different database management systems in relational mode.

As we all know, Java technology is a new programming technology, which has the characteristics of platform independence, object-oriented, security, high-performance, distributed, multithreading and so on, which makes Java the most type of programming language and platform at present. For joint access and data exchange of multi-database systems, Java technology can be used to solve the data processing between different operating systems and different database management systems.

How to use JavaBean technology to access multiple databases

JavaBean is a Java model component that provides a standard format for using Java classes. Information about these classes with standard format can be obtained automatically in user programs and visual management tools, and can be created and managed.

Multi-database access based on Web is a form of multi-database joint application with the rapid development of e-commerce and e-government. Under the condition of heterogeneous database and heterogeneous operating system, only Java technology can solve the problem of multi-database application with large amount of data.

For multi-database access under Web, the new technology of Java is Servlet. JavaServlet is a Java program that runs on the server side. Now with the introduction of the ServletAPI2.3 version, the server's Servlet will take JavaWeb software development to a higher level. Servlet provides a fast, powerful and flexible development environment. The developed Servlet can run in the process space of the server and can handle multiple requests at the same time. Of course, the most commendable thing is Servlet's platform independence.

For multi-database access based on Web, JavaBean technology can provide a powerful and flexible solution. First of all, we construct multiple JavaBean. In these model components, we have to deal with database connection, definition, search, insert, delete and other methods, and to implement multithreading, and then construct a Servlet that calls JavaBean, so that we can access multiple databases. The structure of JavaBean is as follows:

PublicclassDatabaseConnectBean

{

Define the members of the database connection

The method of defining the connection {}

……

}

The procedure for calling JavaBean in Servlet is:

PublicclassUsedatabaseBeanextendsHttpServlet

{

PublicvoiddoGet (httpServletRequestreq,HttpServletResponseresp)

ThrowsServletException,IOException

{

……

}

PublicvoiddoPost (httpServletRequestreq,HttpServletResponseresp)

ThrowsServletException,IOException

{

……

/ / create an object for JavaBean

DatabaseConnectBeanconBean=newDatabaseConnectBean (…)

/ / use conBean to operate the database

……

}

}

From the above procedures and statements, we can find that different types of databases can be accessed by using Servlet technology, but in order to ensure the consistency of database data by using JavaBean technology under Servlet technology, we can use synchronization in Java thread technology to realize database connection and operation in JavaBean, but this will increase the programming realization of programmers. Therefore, using JavaBean under Servlet technology can access multiple database entities at the same time, but it is not convenient to implement.

At this point, I believe you have a deeper understanding of "how to solve the Java multi-database system". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.