当一个线程在运行的时候，不管是上传还是下载，你可以查询进程状态并且给用户一个反馈（例如一个进度条）。
While a thread is running, either uploading or downloading, you can query it to check on its status to provide the user with feedback (e.g. a progress bar).
当评估查询执行计划时，优化器计算并比较每种连接方法的成本，然后选择要使用的最佳方法。
The optimizer calculates and compares the costs of each join method and selects the best one to use when evaluating query execution plans.
当表非常大或者大量会话发出这种类型的查询时，性能将会有所下降。
Performance is negatively impacted when the table is large or when many sessions issue this type of query.
当查询被提交到DB 2后，将以一种最适合优化的方式重写它。
When a query is submitted to DB2, it is rewritten in a form that is most suitable for optimization.
当优化器创建查询计划时，它将使用下列系统目录信息。
The optimizer USES the following system catalog information as it creates a query plan.
当出现提示时，您可以直接键入查询语句或者使用向导帮助您创建一个查询语句。
When prompted, you can type in your query statement directly or use the wizards to help you create one.
当计划查询时，查询编译器使用这些特征和约束。
The query compiler uses these characteristics and restrictions when planning the query.
当从应用程序代码中使用SPARQL时，避免把数据集绑定到查询是一个好习惯——例如，它允许把同一查询重用在不同的图上。
Avoiding binding the dataset to the query is good practice when using SPARQL from application code — it allows the same query to be reused with different graphs, for instance.
再次查询总结表，又是没有返回数据，但是当执行了REFRESHtable语句之后，查询得以成功运行。
Another query against the summary table returns no data, but after the REFRESH table statement executes this time, the query runs successfully.
当该应用程序发出任何数据库请求(例如一个SQL查询)时，该代理就会出来执行完成这个查询所需的所有任务——它代表该应用程序工作。
When the application issues any database requests, such as a SQL query, the agent goes out and performs all the tasks that are required to complete the query - It works on behalf of the application.
如果查询使用没有进行索引的列的组合，那么当执行查询时，GAE将只在运行时出现一个异常。
If a query USES a combination of columns that are not indexed, GAE will only throw an exception at run time when the query is executed.
范例：您可以运行一次查询，然后当后台运行查询时开始处理一次缺陷。
Example: You can run a query, then start working on a defect while the query is running in the background.
当DB 2优化器为一个查询形成查询访问计划时，它将工作划分到多个数据库分区上，这些数据库分区是并行工作的。
When the DB2 optimizer forms a query access plan for a query, it divides the work among the database partitions which work in parallel.
当一个查询引用一个函数模板时，查询优化器尝试生成一个灵活的计划，允许在远程数据源上计算这个函数引用。
When a query references a function template, the query optimizer tries to generate a feasible plan that allows this function reference to be evaluated on the remote data source.
当您单击格式化查询中任意一行时，其他包含来自同一张表的列或表引用的查询的行也会高亮显示。
When you click any line in the formatted query, other lines of the query that contain column or table references from the same table are also highlighted.
当连接器执行查询时，它试图将查询返回的列名与在连接器阶段的输出链接中指定的列名匹配。
When the connector executes a query, it tries to match the column names the query returns with the column names specified on the output link of the connector stage.
当创建并填充好MQT之后，一个任意的后续查询就会由MQT来满足，条件是MQT匹配该查询的所有部分或一部分。
After the MQT is created and populated, an arbitrary subsequent query may be satisfied by the MQT if the MQT matches all or a part of the query.
另一个用途是当DB 2查询优化器确定只需检查分区的一个子集来回答特定查询时，基于分区消除以提高性能。
Another purpose is to improve performance based on partition elimination when the DB2 query optimizer determines that only a subset of the partitions need to be examined to answer as particular query.
当提交该查询时，查询编译器会分析它的语法和语义。
When the query is submitted, its syntax and semantics are analyzed by the query compiler.
这是用RDF表示查询的常用方法，尽管当查询变得更复杂时，它会显得比较笨拙。
This is a common approach to representing queries in RDF, although it gets unwieldy as queries get more complex.
当查询准备好后，数据库将分析、编译和优化执行该查询的计划。
When the query is prepared, the database will analyze, compile and optimize it's plan for executing the query.
当发出下面的查询时，查询优化器将检测到该查询可以用一个MQT来回答，因而可能会选择访问该MQT的一个访问计划。
When the following query is issued, the query optimizer will detect that the query can be answered using an MQT, and may choose an access plan that accesses the MQT.
当执行静态查询时，会使用以前生成的查询计划。
When a static query is executed, the previously computed query plan is used.
当设置了该选项时，查询优化器选择按照PDA的指示将大部分工作下推到数据源的查询执行计划。
When this option is set, the query optimizer chooses the query execution plan that pushes the most work down to the data source as indicated by the PDA component.
当您的要求变得更加具体时，这些查询的复杂性也缓慢增加。
The complexity of the queries slowly increases when your requirements become more specific.
当使用“强制”选项时，当前会话的所有查询只要可能就使用星型连接计划。
When the "forced" option is used, star join plans will be favored whenever possible for all queries in current session.
当您为每个域创建索引时，您可以决定查询是否要支持区分大小写。
When you create the index for each field, you can decide whether queries will be case-insensitive or case-sensitive.
当然，当继承条件扩展到原生查询中时，其功能就跟我所做过的简单对象查询一样强大。
Of course, inheritance criteria extends into native queries just as strongly as it does the simple object queries I've done so far.
例如，当某个特定查询返回几千行给最终用户时，要慎重处理。
For example, proceed cautiously when a particular query returns thousands of rows to the end user.
例如，当某个特定查询返回几千行给最终用户时，要慎重处理。
For example, proceed cautiously when a particular query returns thousands of rows to the end user.
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