直接使用SQL会使缓存出问题，因为缓存层必须处理完整的结果集，而不是单独一个数据库行。
Directly using SQL makes caching problematic, since the caching layer must deal with full result sets rather than single database rows.
数据库层必须尽可能没有延迟地处理环境中的事务。
The database tier has to process transactions in an environment as near latency-free as possible.
由于大部分数据库层支持能更好地处理该风险的准备语句，禁用该设置会再次消除这个烦人的性能问题。
Since most database layers support prepared statements that handle this risk much better, turning this off will again remove an annoying performance problem.
驱动程序层显示花费在执行数据库驱动器处理逻辑上的时间。
The driver layer shows times spent performing database driver processing logic.
该层将一段源id映射到物理数据库，对于同一个物理地址的表，通过建立树来处理。
A forwarding layer maps ranges of source IDs to physical databases, and replication is handled by building a tree of such tables under the same forwarding address.
业务层和数据库没有任何通讯-这些有数据访问层处理。
The Business Layer does not have any direct communication with the database - this is all handled by the Data Access Layer.
例如，度量指标汇总和计算可以传递到数据库层进行处理，而不是在Transformer中处理。
For example, measure aggregation and calculations can be passed to the database layer for processing rather than having Transformer process them.
在两层的客户端应用模型中，人们甚至会直接从事件处理器中访问数据库。
In 2-tier Client application models people were even accessing the database directly from the event-handlers.
SpringDAO：JDBC DAO抽象层提供了有意义的异常层次结构，可用该结构来管理异常处理和不同数据库供应商抛出的错误消息。
Spring DAO: the Spring JDBC DAO abstraction layer offers a meaningful exception hierarchy for managing the exception handling and error messages thrown by different database vendors.
不仅需要对付Struts，还必须处理数据层以及数据层与数据库暗含的耦合！
Not only do you have to contend with Struts, you also have to wrestle with the data layer and its implicit coupling to a database!
教学管理数据库主要用于储存管理应用处理层所需的数据资料。
Educational administration database is used primarily for depositing the needed data of the application layer.
模型层：主要负责业务的处理逻辑实现与数据库的交互等，是该系统的主要计算单元。
Model layer: responsible for handling business logic interacts with the database, are the system 's main computing unit.
业务层处理数据，业务层处于表示层和数据库层的中间，提供表示层所需的数据，它实际的角色是表示层和数据层的中介。
The logic layer is responsible for the data processing, and it locates between view layer and database layer providing the data for the view layer.
业务层处理数据，业务层处于表示层和数据库层的中间，提供表示层所需的数据，它实际的角色是表示层和数据层的中介。
The logic layer is responsible for the data processing, and it locates between view layer and database layer providing the data for the view layer.
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