当索引列的顺序是随机的时候,将会发生什么呢?
按照您想应用索引列谓词的顺序创建您的索引。
Create your indexes in the order in which you want those index column predicates applied.
关系索引的数据类型始终由索引列的类型来确定。
The data type of relational indexes is always determined by the type of the indexed column.
但是如果索引列的顺序是随机的,将会发生什么呢?
But what happens when the order of the index column is random?
选项可以指定全文索引列的默认语言值。
Option to specify a default language value for full-text indexed columns.
任何利用主索引列的查询将会遭遇更快速响应时间问题。
Any query that utilizes the Primary Index column will encounter faster response times.
否则表中的所有全文索引列必须使用相同的语言。
Is specified, the language of all full-text indexed columns in the table must be the same.
在某些情况下,联接非索引列会使查询速度变慢。
In some cases, joining on unindexed columns can result in a slow query.
有太多的数据项保存于没有过滤和索引列的列表中。
Too many items in the list without using filters and indexed columns.
常见的替代项包括索引列或其他唯一键列的群集。
Common alternatives include clustering index columns or other unique key columns.
但是如果索引列的顺序是随机的,将会发生什么呢?
Butt what happens when the order of the index column is random?
创建全文索引时,建议为每个索引列都指定一种语言。
When creating a full-text index, we recommend that you specify a language for each indexed column.
另外,DB 2无法在排序合并合并连接中使用随机顺序的索引列。
Also, DB2 cannot use random order index columns as part of a sort merge join.
语言分析规则因语言而异,可以为每个全文索引列指定不同的语言。
The rules for this analysis differ for different languages, and you can specify a different language for each full-text indexed column.
定义惟一索引的索引规范还将关于索引列惟一性的信息传递给联邦系统。
An index specification that defines a unique index also conveys information about the uniqueness of the index columns to the federated system.
为此,索引列是一个包含索引的单列,或者是复合索引中指定的第一个列。
For this purpose, an indexed column is any single column with an index or the first column named in a composite index.
重建将自动重建所有索引列统计信息,而重新组织根本不会更新统计信息。
REBUILD will automatically rebuild all index-column statistics, whereas REORGANIZE won't update statistics at all.
示例13:收集构成索引的所有列以及两个非索引列中包含分布的目录统计信息。
Example 13: Collect catalog statistics with distribution on all columns that are part of the index, plus two columns that are not.
当超过这个限度后,确实存在性能影响。有一些方法可以克服这个限度,就是使用索引列和视图。
There are definitely performance impacts when exceeding this limit and there are ways to overcome this limit by using indexed columns and views.
为了展示这一点,将它与计划中第5号索引扫描上使用的谓词相比较,它针对子表中惟一的索引列。
To illustrate this, compare it to the predicate that is applied to the index scan numbered 5 in the plan, which is on the one and only column of the index on the child table.
这份地图所使用的符号全部列在索引中。
我们可以使用随机化的索引键列来减少争用,但这有何代价呢?
We can use randomized index key columns to reduce contention, but at what cost?
将这些列放在索引的开始部分。
例如,您可以决定哪些索引或列将受到处理过程的影响。
For example, you can influence which indexes or columns are affected by the processing.
确保查询中进行连接操作的列都有索引。
Ensure that columns that are joined in queries have indexes.
编写报告时,要尽可能确保利用具有索引的列。
When authoring reports, be sure to leverage columns that have indexes wherever possible.
函数索引对列中的数据进行转换并按照顺序保存转换后的值。
A functional index transforms the data in a column and stores the derived values in sorted order.
当索引了一列时。
这包括表、别名(nickname)、索引、列和用户定义的函数(UDF)的统计信息。
This includes statistics for tables, nicknames, indexes, columns, and user-defined functions (UDFs).
这包括表、别名(nickname)、索引、列和用户定义的函数(UDF)的统计信息。
This includes statistics for tables, nicknames, indexes, columns, and user-defined functions (UDFs).
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