SAP R/3 Instances and Clients
SAP R/3 实例与实集
An SAP R/3 implementation is usually performed with more than one R/3 “system.” As with any software and database, the environments where configuration is performed and where new programs are written and tested should not be the same environment where the system is used on a day-to-day basis. SAP accommodates the need for these separate environments with instances and clients.
一个SAP R/3项目的实施通常不止使用一个R/3“系统”。就象任何软件和数据库一样，配置用的环境和程序编写和测试的环境应该是在与日常使用系统所在的环境不同的环境。SAP使用实例(instance)和实集(client)来满足这些分离环境的需求的。
An instance is typically named for the type of environment it supports, it often has a three-character name, and its data is contained in a separate database from other instances. An instance named DEV, for example, would indicate that development work would be performed on this instance. An instance named PRD, for another example, would indicate that this instance is used for “production,” or day-to-day use, and programming, configuration, and testing should not be performed in this instance. Once configuration settings are satisfactory in a particular instance, they will be transported to another instance. Transporting will be discussed later. There are typically three or more instances defined. The purposes of each instance include (but are certainly not limited to) development & testing, quality assurance, and production.
一个实例通常是按照其所支持的环境类型来命名的，通常有一个由三个字符组成的名字，它的数据存放在与其它实例分开的一个数据库中。例如，一个名为DEV的实例表明在这个实例上要进行开发工作。再比如，一个名为PRD的实例表明该实例是用于“生产”，即日常使用，编程、配置和测试不应在该实例中执行。一旦配置设置在某个具体的实例中得到满意结果，它们将被传输到另一个实例。每个实例具有不同的用途，包括（当然并不限于）开发与测试、质量保证和生产。
A client, in SAP terms, indicates a “subsystem” within an instance, and is indicated by a number, usually three digits. A PRD (productive) instance will likely have only one client (that is usable). That instance and client combination may be referred to as PRD100, for example. Other instances may contain a number of clients, particularly if some development, configuration, program development, testing, or training must be done without affecting or being affected by other work currently being performed.
一个实集(client)，按SAP术语理解，表示的是一个实例(instance)的一个“子系统”，是一个数字表示的，通常为三位数。一个PRD (生产)实例将可能只有一个实集（是可以使用的）。这个实例与实集的组合可以称为，比如，PRD100。其它的实例可以包含几个实集，特别是如果某些开发、配置、程序开发、测试或培训工作必须不影响其它正在执行的工作或不受这些工作的影响。
It is common to see a DEV instance with clients such as 100, 200, 300, and so on defined. In such a case, DEV100 may be the instance/client that is considered the “clean” source for the configuration that will be used in the production instance & client, perhaps PRD100. DEV200 might be used for configuration testing. While much configuration is client-specific (if it is configured in DEV200, for example, it only affects DEV200), some configuration is cross-client or not client specific (if it is configured in DEV200, it affects every client in the DEV instance—100, 200, 300, and so on). Usually, the system will provide a warning that a configuration step is cross-client.
一个DEV实例有几个实集是很常见的，比如象100、200、300等等这样定义的实集。在这种情形下，DEV100可以作为是“清洁”配置源的实例/实集，它的配置将被用于正式生产性的实例/实集中，可能称为PRD100。DEV200可以用于测试配置结果。虽然许多配置是针对具体实集的（例如，如果配置是在DEV200完成的，它只会影响DEV200），有些配置是跨实集的，即不是针对具体实集的（如果配置是在DEV200中完成的，它将影响DEV实例中的所有实集 – 100、200、300等等）。通常系统会警告说某个配置步骤是跨实集的。
Programming (ABAP programming and so on) is usually cross-client. If a programmer activates a program in DEV300, for example, it will affect DEV100, DEV200, DEV300, and so on. It is for this reason, in part, that during some SAP R/3 implementations, a separate instance may be reserved for program testing.
编程（ABAP编程等）通常是跨实集的。例如，如果一个程序员在DEV300中激活一个程序，它将影响DEV100、DEV200、 DEV300等实集。正是部分地因为这个原因，在SAP R/3实施期间，会给程序测试预留一个单独的实例。
As discussed earlier, SAP “systems” are organized into “instances, ” each of which contains one or more “clients.” Examples of instances are DEV (for development and configuration), QAS (for quality assurance) and PRD (for the productive system). There may be more instances, but rarely less.
如早先已经讨论的，SAP“系统”是组织成“实例(Instance)”的形式的，每个实例包含一个或多个“实集(Client)”。实例的例子有 DEV（用于开发和配置），QAS（用于质量保证）和PRD（用于生产系统）。（一个实施项目）可能会有比这些实例更多的实例，但是很少会有更少的。
Each instance (DEV, QAS, PRD, etc.) may consist of more than one client.
The clients are typically identified by a three-digit number, such as 100, 110, 120, 200, etc. Each client within an instance can share SAP R/3 programs, but will have its own transactional data. Some configuration will affect all of the clients in an instance, but some configuration will only affect the client in which it has been performed. Each unique combination of instance and client is identified as “DEV100, ”“DEV 120” and “QAS100, ” for example. Since the productive/production instance normally contains only one (accessible) client, it is often referred to simply as “PRD.” Instances and clients will be discussed again later.
每个实例（DEV, QAS, PRD等）可以由不止一个实集（Client）组成。这些实集通常是用三位数的数字来识别身份，例如100, 110, 120, 200等。一个实例中的每个实集可以共享SAP R/3程序，但是将拥有自己的事务数据。某些配置将影响一个实例中的所有实集，但是有些配置只会影响设置这个配置的那个实集。每个唯一的实例实集组合是以诸如“DEV100”、 “DEV 120” 和“QAS100 ”等来识别身份的。由于生产（性）实例通常只包含一个（可使用的）实集，它通常简单地称为“PRD”就足够了。（本书）将在以后对实例和实集做进一步讨论。