为了成功生成部署环境，您需要确保有数据库实例存在。
For the deployment environment generation to succeed, you need to make sure that the database instances exist.
此功能检查如果实例存在，如果是这样，它返回。
This function checks if the instance exists - if it does, it returns it.
单例模式是一种有用的控制类访问的途径，他能保证只有一个类实例存在。
Singletons are a useful way to control access to a class, making sure that only one instance can exist.
您还可以指定这些属性必须与另一个业务模型的实例存在一定的关系，比如负责这个硬件的所属公司。
You can also specify that there must be a relationship to an instance of another business model, perhaps the owning organization in charge of the hardware.
由于单例对象作为实例存在而不是类的静态成员，所以你能够惰性地初始化单例对象，即只需要在第一次用它的时候才去创建它。
With singletons implemented as single instances instead of static class members, you can initialize the singleton lazily, creating it only when it is first used.
也许更多类似的测试最终会给研究人员提供他们正在寻找的证据，并加强心灵感应存在的实例。
Perhaps more tests like these will eventually give the researchers the evidence they are seeking and strengthen the case for the existence of telepathy.
第一个宣称这个计数器实例对象不是空，就像它实际存在一样。
The first one asserts that the calculator instance object is not null, i.e. it exists.
如果不存在模板的运行流程实例，您现在无需首先停止模板即可卸载应用程序。
If there are no running process instances for a template, you can now uninstall the application without having to first stop the template.
对于消息流实例的所有节点而言，只存在环境树的一个副本，消息树将被复制到所传播到的每个节点。
Only one copy of the Environment tree exists for all the nodes of the message flow instance but for Local Environment, the message tree is copied for every node it is propagated.
如果安装某个业务流程或人工任务的新版本，通常旧版本的实例仍然存在。
If you install a new version of a business process or human task, usually instances of the old version still exist.
当某个模板不再存在任何实例时，可以通过卸载对应的企业应用程序删除该模板。
When no instances exist anymore, you can remove a template by uninstalling the corresponding enterprise application.
也许存在这样的情况，就是实例中使用的富文本标记不是XHTML。
There may be a scenario where the rich text markup that the instance USES is not XHTML.
存在多个业务流程实例时，需要能够唯一地标识返回响应的流程实例。
When there are multiple process instances, you need to be able to uniquely identify the process instance that returns the response.
只要对业务逻辑的所有修改仍然在新实例中存在，就可以迁移实例。
Instances can be migrated, as long as all changes to the business logic are still in the future instance.
因此，结果仅返回第一个实例中的地址，因为第二个实例中不存在元素。
Therefore, the result returns only the addresses from the first instance because the element does not exist in the second instance.
类是一直存在的，而实例具有有限的生命周期。
The classes last forever, and the instances have a limited lifetime.
集群环境中单独的服务器实例作为集群成员而存在。
The individual server instances in a cluster environment are referred to as cluster members.
特别地，它存在类实例之间的交互作用。
Specifically, it presents interactions between class instances.
对于可能存在多个MXBean实例的那些MXBean类型来说，存在着工厂方法，可以在List中返回MXBean，如清单2所示。
For those MXBean types where multiple instances of the MXBean may exist, there are factory methods that return the MXBeans in a List, as shown in Listing 2.
max_coordagents参数是可以存在于实例中的协调代理的最大数量。
The max_coordagents parameter is the maximum number of coordinating agents that can exist in the instance.
比如，图3中的实心菱形表示这里是组合关系——换句话说，address类的实例只能存在于person类的上下文中。
For example, in Figure 3 the solid diamond indicates that the relationship is a composition — in other words, that instances of the address class can only exist within the context of a person class.
第一，将实例从堆栈弹出后，Dispose方法将检查堆栈中是否还存在任何剩余的实例。
First, after popping an instance from the stack, the Dispose method checks to see whether there are any remaining instances on the stack.
对于每个容器管理的em实例，都存在一个或多个对应的容器管理的持久性上下文(Persistence Contexts,PC)。
For each container-managed EM instance, there are one or more corresponding container-managed persistence contexts (PC).
必须对 iFrame名称进行编码，以防止在页面上存在Portlet的多个实例时出现冲突。
You must encode the iFrame name to prevent potential conflicts when more than one instance of the portlet is on page.
不同的是，使用class= 时，如果bean 在指定范围内不存在，可以实例化一个 bean。
The difference is that, with class=, if the bean does not exist within the specified scope, one is instantiated.
在清单3中，是为一个不存在的文件实例化了File对象。
In Listing 3, you instantiated a file object for a file that didn't exist.
静态Current属性使用Stack.Peek方法返回位于堆栈顶端的T实例（如果存在），如果Stack 为空则返回空。
The static Current property uses the Stack.Peek method to return the T instance at the top of the stack if one exists, returning null if the Stack is empty.
由于DB2实例可以包含多个数据库，因此存在两个级别的配置。
Since a DB2 instance can contain more than one database, two levels of configuration exist.
目前大公司基础架构中存在的数据库实例已经开始使用基础架构即服务平台，并使用已有的许可协议。
The database instances that exist today in large enterprise infrastructures started with an infrastructure as a service platform using license agreements that already exist.
目前大公司基础架构中存在的数据库实例已经开始使用基础架构即服务平台，并使用已有的许可协议。
The database instances that exist today in large enterprise infrastructures started with an infrastructure as a service platform using license agreements that already exist.
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