If you need to wait on a blocking action — say, the results from a remote database query — it is not clear exactly how long you will need to wait for results to be available.
如果您需要等待一个阻塞操作—比如，对于来自远程数据库查询的结果—您不会确切地知道在可以使用结果之前究竟要等待多长时间。
By adding code to manage query caches for multiple users at the same time in a single process, the process need not be suspended, but can be switched to perform work for another user.
通过添加代码来同时在单个进程中管理多个用户的查询缓存，不需要挂起进程，而可以进行切换来为另一个用户执行工作。
However, the following query does not need an extra sort since the query access is limited to a single partition.
然而，由于下面的查询访问限制在单个分区上，因此不需要额外的排序操作。
You should also be selective in your query so that the database does not return more rows and columns than you need.
您还应该使查询具有可选择性，这样数据库就不会返回您不需要的行和列。
However, in most cases, you do not need to perform query tuning manually.
尽管如此，大多数情况下，您不需要手工执行查询调优。
Of course, not many of us would need (or want, for that matter) to retrieve the entire database with a single HQL query.
当然，我们之中没有多少人需要只用一个HQL查询检索整个数据库。
Using a text index makes document search much more efficient, as the text data does not need to be examined at query time like it is done with sub-string matching.
使用文本索引使文档搜索的效率大大提高，因为不需要像进行子字符串匹配时那样在查询时检查文本数据。
Figure 1 is for a simple query where the results from individual slices need not to be processed further in memory.
图1是一个简单的查询，其中来自各个片的结果无需在内存中做进一步的处理。
Object query languages still do not relieve you from having to know SQL, since you often need to know how to fine tune query languages.
对象查询语言仍不能免除必须了解SQL，这是因为通常需要了解如何调优查询语言。
If the cache is not complete, you need to go back to the database to perform the query instead.
如果缓存不完整，您需要返回到数据库执行查询。
Armed with my knowledge of the search count, I may need to enter the interactive query mode (the user is asked if he wants to do so, and if not, the program quits gracefully).
有了检索计数知识，可能需要进入交互式查询模式(用户会被询问是否希望这样做，如果不，程序会温柔地退出)。
Also, it is clear that the XML that is being used in the query does not even need to exist in the database.
另外，查询中使用的XML甚至不需要在数据库中存在。
Directing a query to the appropriate shards is handled automatically, so applications do not need to keep track of which shard holds what data elements.
MongoDB会自动将查询引导到合适的分片上，因此应用程序并不需要了解哪个分片持有什么数据元素。
A user does not need to change the query in order to make use of the MQT.
为了使用MQT，用户不必要更改查询。
When the first message passes through the flow and USES this query, there will be no latency, since the node will not need to call to Registry and Repository and will use the cached results.
当第一条消息通过流并使用此查询时，将不存在延迟，因为节点不需要调用Registry andRepository，并将使用缓存的结果。
Many applications do not need the full power of the Lucene query Parser Syntax, especially the use of wildcards and other more advanced query types.
很多应用程序都不需要LuceneQueryparser语法的全部，尤其是使用通配符和其他高级查询类型的情况下就更是如此。
If there is no index on ucname, the DBMS still does a full table scan, but it need not do any further processing on the data to determine whether or not it satisfies the query.
如果没有为ucname创建索引，DBMS仍然执行全表扫描，但是不会对数据进行进一步处理来判断其是否满足查询。
That's it – blocking occurs not because multiple sessions are trying to update the same data, but because of non-optimized query that needs to process/acquire lock on the data it does not really need.
所以阻塞的发生并不是因为同时有多个会议尝试去更新相同的数据，而是因为没有经过优化的查询申请了锁，但读取到的数据往往是不必要的数据。
In smart space, location-aware applications not only need rapid location-related query service, but also require proactive spatial event service.
智能空间中，位置感知应用不仅需要位置相关的快速查询服务，而且需要伺候式的空间事件服务。
QR-Tree index combines the advantage of Quadtree and R-Tree, not only serves the need of high storing efficiency, but also avoid of many invalidation query, in order to achieve good query capability.
树索引结合四叉树和R-树的各自优点，既可以满足较高的存储效率，又避免太多的无效查找，达到较好的查找性能。
Nevertheless, some indices do not contain all element nodes, many paths need to still be examined in the query;
然而有的索引不包含所有的元素结点，因而在进行查询时许多路径仍需要检测；
Users do not have to master the complex query languages; nor do they have to be aware of the database schema. They only need to enter the keywords to perform a database query.
用户不需要掌握复杂的结构化查询语言，也无需了解数据模式，只需要输入查询关键词就可以进行数据库的查询。
Users do not have to master the complex query languages; nor do they have to be aware of the database schema. They only need to enter the keywords to perform a database query.
用户不需要掌握复杂的结构化查询语言，也无需了解数据模式，只需要输入查询关键词就可以进行数据库的查询。
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