Vertical scaling is typically employed for the database tier.
纵向扩展通常用于数据库层。
Listing 3 shows XML fragment for a database tier with two server groups.
清单3给出包含两个服务器组的数据库层的xml片段。
New components could reuse database tier functionalities where possible.
在可能的情况下，新组件可以重用数据库层的功能。
The database tier of current applications is known to be very well structured and efficient.
已知当前应用程序的数据库层结构非常良好和高效。
There should not be any affinity between the web tier, application tier and the database tier.
Web层，应用层和数据库层之间不应该有任何交叉。
Configure the database tier and the application tier for production. Migrate the database tier.
为生产运行而配置数据库层和应用程序层。
The database tier has to process transactions in an environment as near latency-free as possible.
数据库层必须尽可能没有延迟地处理环境中的事务。
As it turns out, Seam can also help take a load off of the limited resources of the database tier.
结果，Seam还能帮助降低数据库层有限资源的负载。
Each product was divided into tiers: a database tier, an application tier, and a Web server tier.
每个产品都划分为多个层：数据库层、应用程序层和Web服务器层。
For example, a mysql-cluster-based database tier would be comprised of two server groups, an NDBD group and a manager group.
例如，基于mysql集群的数据库层可能包含两个服务器组，一个ndbd组和一个manager组。
Now, when the same query is run, the native SQL that is generated is a single select statement joining the two tables from the different catalogs at the database tier as shown in Illustration 10.
现在，当同一个查询运行时，生成的原生sQL是单个选择语句，在语句在数据库层联接来自不同目录的两个表，如图10所示。
This experience approximates the mixed architecture, but is simpler to implement because the presentation tier and application logic are always against the local database.
这种体验比较接近混合架构，但实现起来更加简单，因为表示层和应用程序逻辑始终是针对本地数据库的。
However, the cost of process hopping to the database is still high, thus performance on the data tier is the first place to look when optimizing your code.
然而进程跳跃到数据库的成本依然很高，因此数据层的性能是您在优化代码时首先要考虑的问题。
This support in JDBC 4.0 means that XML can natively flow across the middle tier and the database without unnecessary mapping or performance overhead in both the database and the middle tier.
JDBC 4.0中的这个支持意味着：无需不必要的映射，XML就可以原生地在中间层和数据库之间流动，这也不会在数据库和中间层导致性能开销。
These lightweight sessions reduce the network overhead of creating separate network connections from the middle tier to the database.
这些轻量级会话减少了创建中间层与数据库的连接所带来的开销。
Clearly, there is a need for a mechanism whereby the actual user's identity and database privileges are used for database requests performed by the middle tier on behalf of that user.
显然，需要用一种机制来确保对于中间层代表用户执行的数据库请求，仅使用实际的用户身份和数据库权限。
The database should be able to distinguish the transactions performed by the middle tier for its own purpose, from those performed by the middle tier on behalf of some users.
对于中间层自身执行的事务与中间层代表某些用户执行的事务，数据库应该能够加以区分。
By using XML natively in the middle tier, those same advantages are achieved in the middle tier and more importantly across both the middle tier and the database.
通过在中间层原生地使用XML，可在中间层(更重要的是跨中间层和数据库)实现这些好处。
Data Server tier, part of data Grid, buffers database access by caching objects in-memory for higher performance.
数据服务器层是数据网格的组成部分，通过在内存中缓存对象来缓冲数据库访问，以实现更高的性能。
Then, a 1.2 TB DB2 9.7 LUW database was created on the Tier 0 storage (EFDs).
然后，在Tier0存储（EFD）中创建一个 1.2TBDB2 9.7LUW数据库。
The sequence I follow when performing reads is to take a request (that requires a database query) from the Web tier and check the cache for previously stored results of that query.
我执行读取操作的顺序是从web层获取请求(需要执行一次数据库查询)并检查之前在缓存中存储的查询结果。
Gridscale ACTS as a transactional tier in a database solution.
Gridscale在数据库解决方案中充当事务层。
For these tests, the WebSphere tier was virtualized, but the application database remained on physical hardware.
在这些测试中，对websphere层进行了虚拟化，而应用程序数据库则使用了物理硬件。
Added to this mix is the open source database success of MySQL in the data tier.
在这个组合之上，还可以用开放源码数据库MySQL建立数据层。
The only thing I regret is not having implemented some kind of ActiveRecord-like framework between the PHP tier and the database.
我唯一遗憾的是在PHP层与数据库之间没有实现某种类似ActiveRecord的框架。
If you then had a scripting language running in-process with the Web server, such as PHP, that connected to a database, this would be described as two tier.
如果用Web服务器运行某种脚本语言(比如php)，从而连接数据库，那么这可以看作两层。
This feature of the XQuery makes it possible to push not only the business logic but also the publishing to the database server, in effect making the middle tier application very simple and thin.
使用XQuery的此功能，不仅可以推出业务逻辑，而且可以发布到数据库服务器，从而有效地使中间层应用程序非常简单。
The MySQL database is used in the data tier.
在数据层中使用MySQL数据库。
A better approach is needed for ensuring that each user's database identity and database privileges are used for any database requests performed by a middle tier on behalf of that user.
为了确保对于中间层代表每个用户执行的任何数据库请求，都使用那个用户特定的数据库身份和数据库权限，需要一种更好的方法。
End-to-end performance is improved as there are no copies of the data made between the database (or other XML data source) and the middle tier.
端到端性能得到改进，原因是不需要在数据库(或其他XML数据源)和中间层之间创建数据副本。
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