使用适于XML连接谓词的索引。
带有IN或OR操作符的连接谓词。
三个表用等值连接谓词连接。
丢失连接谓词，只在定义了外键的情况下。
Missing join predicates, but only if a foreign key is defined.
查询2对authors表应用连接谓词。
在这两个查询中，方括号中表示了连接谓词。
In both queries, the join predicate is expressed within the square brackets.
一个原则是禁用in谓词到连接谓词的转换。
A guideline to disable the transformation of the in predicate to a join.
以下查询明确地将连接谓词的两端转换为DOUBLE。
The following query explicitly casts both sides of the join predicate to DOUBLE.
您需要使用本地谓词和连接谓词设计索引，以支持高效访问。
You need to design indexes to support efficient access with local predicates and join predicates.
即，通过连接谓词，CUST_INTEREST表的选择性非常强。
That is, table CUST_INTEREST could be very selective through the join predicate.
如果将xml索引定义为double，则用xs： double转换连接谓词。
If the XML index is defined as double, you cast the join predicate with xs: double.
期间会使用源列上的连接谓词，以及在UNIONALL视图定义中赋给这些列的值。
This USES the join predicates on the source columns, and the values assigned to them in the UNION ALL view definitions.
根据各种标准，如本地谓词或连接谓词，以及表引用来定制谓词的格式化顺序。
Customize the formatting ordering of the predicates according to various criteria such as local predicates or join predicates, and table references.
请注意，authorID上的连接谓词没有包含文字值，该文字值将表明比较的数据类型。
Note that the join predicate on the author ID does not contain a literal value that would indicate the data type of the comparison.
总结一下关于XML连接查询的建议，通常将连接谓词转换为应使用的xml索引类型。
To summarize the advice for XML join queries, always cast join predicates to the type of the XML index that should be used.
如果将xml索引定义为VARCHAR，则用fn：string转换连接谓词，如表6所示。
If the XML index is defined as VARCHAR, you cast the join predicate with fn: string, and so forth as you see in Table 6.
如果在连接谓词中使用分区键（partitioning key），最后还有一点考虑需要顾及。
When you use the partitioning key in the join predicate, a final consideration needs to be mentioned.
一个星型连接查询通常包含一个事实表和几个维度表，事实表和每个维度表之间都有连接谓词。
A star join query typically involves a fact table and several dimension tables, with join predicates between the fact table and each dimension table.
对于cust_order_header表，现有的索引表不支持表上的本地和连接谓词，如下所示。
For table CUST_ORDER_HEADER, both of the existing indexes do not support the local and join predicates on the table, as shown below.
严格来说，DB 2 9.7不一定要使用fn：string来为连接谓词启用varchar索引。
Strictly speaking, DB2 9.7 does not necessarily require the use of fn: string anymore to enable VARCHAR indexes for join predicates.
这些附加的源列，加上用户查询中附加的源连接谓词，可以帮助重写阶段识别不会产生任何连接结果的连接。
These additional source columns, combined with additional source join predicates in user queries, help the rewrite phase identify joins that will not produce any join results.
例如，编写可索引或一阶谓词，尽量不要编写没有连接谓词（也称为Cartesian 连接）的查询。
For example, write indexable or stage 1 predicates and avoid writing queries without join predicates (also known as Cartesian join).
当使用了一个in谓词(或一个等价的or谓词)时，优化器将会考虑使用一个in到join的变换，将一个in谓词转换成一个连接谓词。
When an in predicate (or an equivalent or predicate) is used, the optimizer considers an IN-to-JOIN transformation, converting the in predicate to a join predicate.
由于查询1表达了books表中的连接谓词，所以DB 2 9.1和9.5执行一个扫描authors的表，然后使用索引authoridx 1查找books表。
Since Query 1 expresses the join predicate on the books table, DB2 9.1 and 9.5 perform a table scan on authors and then use the index AUTHORIDX1 to probe into the books table.
这意味着可以使用它们来索引频繁在谓词和连接中使用的所选择的元素和属性。
That means you can use them to index selected elements and attributes that are frequently used in predicates and joins.
当以连接的形式使用in谓词时，优化器将仍会考虑为它检测统计关联。
When the in predicate is used in its join form, the optimizer still considers it for statistical correlation detection.
图的节点是资源和文字，节点之间用有向边连接，边上用谓词标记。
The nodes of the graph are resources and literals, and they are connected by directed edges, which are labeled with predicates.
因此，编写xmlexists谓词的方式可以影响以前的DB 2版本连接顺序。
Thus, the way you write the XMLEXISTS predicate can affect the join order in these previous versions of DB2.
如图13所示，连接和本地谓词现在在昵称之上。
As shown in Figure 13, the join and the local predicates are now above the nicknames.
使用了哪些种类谓词来连接引用表？
What kinds of predicates are used to join the referenced tables?
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