这表示 explain是用于解释查询的。
This tells us that the explain was used to explain the query. Snippet of the plan
示例连接器：解释查询。
与ItemFinder不同，Query还需要一些相当简单的解析，以便正确地解释查询表达式。
Query, unlike ItemFinder, also requires some relatively simple parsing to interpret query expressions correctly.
重复上面的步骤，再次解释查询，生成查询访问计划之后，优化器会计算出一个更好的、与实际结果很接近的基数估计值。
After repeating the above steps to explain the query again to generate the query access plan, the optimizer computes a better cardinality estimate that is very close to the actual result.
在DOM中的任何其他节点开始，使用一个变量名开始查询表达式，在解释查询表达式时，变量名将与该节点关联。
To start at any other node in the DOM, start the query expression with a variable name that will be associated with that node when the query expression is interpreted.
为了确保能得到有意义的结果，我们还像后面一个小节中解释的那样，检验网格索引是否真正被用于这个查询。
To ensure that we got meaningful results, we also verified that the grid index is actually exploited for this query as explained in a later section.
运行您希望为之收集片段解释的查询。
Run the query you would like to collect section explain for.
DB 2提供的GUI和命令行工具可以用来查看查询的解释计划。
DB2 provides GUI and command line tools to see explain plan of a query.
在研究查询执行计划的问题时，片段解释和片段实绩是非常强大的特性。
Section explains and section actuals are very powerful features to investigate problems with a query execution plan.
我们首先在第一个会话中(本例中是SESSION1)发出主查询，这样我们就能够得到运行时片段解释的目标。
We first issue the main query from one session (SESSION1 in this example) that we would like to see the runtime section explain for.
查询的其他部分在前面已经解释过了。
SQL解释工具提供查询优化器为 SQL语句所选择的访问计划的有关详细信息。
The SQL explain facility provides detailed information about the access plan that the query optimizer chooses for an SQL statement.
我们使用前面的同一个示例查询来说明如何解释星型连接计划的SETEXPLAIN输出。
To show how to interpret SET EXPLAIN output for star join plans, we use the same example query as before.
使用EXPLAIN命令查看查询的解释计划。
如果查询工作负载导致创建许多TEMP表（您可以通过使用解释实用程序来确定）时除外。
The exception would be if the query work load results in many TEMP tables being created (you can determine this by using the explain utility).
当选择一个建议时，突出显示sql行，显示对如何重写查询的说明以及对建议的解释(见图1)。
When you select a recommendation, the line of SQL is highlighted, and you are presented with a description of how to rewrite the query, as well as an explanation of the recommendation (see Figure 1).
例如，某些业务需求是通过分析现有报表查询工作流和解释当前业务数据分析结构而生成的。
For example, some business requirements are generated by analyzing existing report query workflows and interpreting current business data analytic structures.
查询解释使用EXPLAIN命令查看查询的解释计划。
Query Explain Use EXPLAIN command to see the explain plan of a query.
它还可以从SQL缓存捕获查询并生成解释计划。
It can also capture queries from SQL cache and produce the explain plan.
本文解释如何收集SQL性能监视器，以及理解很多SQL查询在如何使用SQE，为什么其他sql语句继续使用CQE。
This article explains how to collect an SQL Performance Monitor and understand how many of the SQL queries are using SQE and why other SQL statements continue to use CQE.
使用提示、解释计划和分析的查询优化特性。
Query optimization features using hints, explain plans, and profiling.
现在，如果用VisualExplain或db 2 exfmt解释此查询，就会看到这个不区分大小写的搜索使用了索引。
Now, if you explain the query (with Visual explain or db2exfmt), you see that the index is used for the case-insensitive search.
重写后的查询也称为“OptimizedSQL”，它将在使用db2exfmt命令解释语句时出现。
The rewritten query known as "Optimized SQL" is visible when you explain the statement with the db2exfmt command.
改善的统计信息收集和查询解释文件。
上面将仅仅以解释模式编译查询。
The above will only compile the query in explain mode. You should see the following on the screen.
阐释如何解释联邦查询执行计划。
Illustrates how to interpret a federated query execution plan.
查询多个文档的需要解释了设计XQuery的原因，这种正在开发之中的原生xml文档查询语言以XPath2为基础。
The need to query multiple documents explains the design of XQuery, the developing query language for native XML documents, which is in turn based on XPath 2.
本文解释一些比较复杂的特性，包括如何动态地执行复杂的OpenSQL查询。
This article explains some of the features that are not entirely straightforward, including how complex Open SQL queries can be executed dynamically.
我只准备解释如何查询包含名称空间的XML数据，因为您在工作当中很可能会遇到名称空间。
I'll just explain how you can query XML data that contains namespaces, because you'll probably encounter namespaces in your work.
这个查询有两个方面要解释一下。
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