In the project implementation process, many users need to develop a new SQL Server-based system. After the system is accepted, it should be merged with an original SQL server system, A single server is shared, so a separate server cannot be provided for the new system (a separate server cannot be provided for development ). However, to ensure the development of the new system without affecting the normal operation of the old system, the new system must use an independent SQL Server service. In versions earlier than SQL Server 2000, such requirements cannot be met, but in SQL Server 2000, on the basis of the original SQL server instance, add another instance to solve the problem.
The so-called "instance" is an SQL Server database engine. SQL Server 2000 supports running multiple SQL Server database engine instances on the same computer at the same time. Each SQL Server database engine instance has a set of systems and user databases that are not shared by other instances. Application Program The method for connecting to an SQL Server database engine instance on the same computer is basically the same as that for connecting to an SQL Server database engine running on another computer. Because each instance has a set of systems and user databases that are not shared by other instances, the operation of each instance is independent, and the operation of one instance is not affected by the operation of other instances, it does not affect the operation of other instances. Installing Multiple SQL Server instances on a computer is equivalent to simulating this computer into multiple database servers, and these simulated database servers run independently and simultaneously.
There are two types of instances: Default instance and named instance. A computer can have only one default instance or no default instance. The default Instance name is the same as the computer name, changing the computer name will modify the default Instance name synchronously (SQL Server 7.0 can only be installed as the default instance. After changing the computer name, the SQL Server service cannot be started, you must execute the SQL Server Installation Program for automatic repair to solve the startup problem). When the client connects to the default instance, the computer name that installs the SQL server instance will be used.
When installing SQL Server 7.0 and SQL Server 2000 on the same computer, since SQL Server 7.0 can only be installed as the default instance, you should first Install SQL Server 7.0, install SQL Server 2000 as a named instance. Alternatively, when installing SQL Server 2000, specify the installation as a named instance.
Multiple named instances can be installed on one computer. When a client connects to a named instance, the format of the following computer name and Instance name combination must be used:
Computer_name \ instance_name
