The index rows will not be in LASTNAME order within DEPTNO A01.
在DEPTNO A 01中,索引行将不以LASTNAME顺序排列。
For the deptno column, num_freqvalues is 0, and num_quantiles is 0.
对于deptno列,num _ freqvalues是0,num _ quantiles是0。
For the deptno column, num_freqvalues is 5 and num_quantiles is 10.
对于deptno列,num _ freqvalues 5, num _ quantiles是10。
And we also started by creating an index on the EMPNO and DEPTNO columns.
我们还从创建关于EMPNO和deptno列的索引开始。
LASTNAME is in random order within each DEPTNO, but like values are contiguous.
LASTNAME在每个DEPTNO内按随机顺序排列,但like值是连续的。
Since both LASTNAME and DEPTNO are part of the index, we will get index-only access.
因为LASTNAME和DEPTNO都是索引的一部分,我们将获得仅限索引的访问。
In this case, there are two column groups: (deptno, deptname) and (admrdept, location).
本例中,总共有两个列组:(deptno, deptname)和(admrdept, location)。
Under the Result Attributes tab, deselect all attributes except "deptname" and "deptno."
在标签 Result Attributes 之下,取消对除“deptname”与“deptno”之外所有属性的选择。
Example 18: Collect catalog statistics on all indexes and on columns deptno and deptname.
示例18:收集所有索引以及列deptno和deptname上的目录统计信息。
On the primary key Tasks page, select deptno as the primary key for the Department entity.
在主要关键字Tasks页面中,选择deptno以作为Department实体的主要关键字。
The num_freqvalues and num_quantiles values for the deptno column will be obtained from the default.
deptno列的num _ freqvalues和num _ quantiles值将从默认值中获得。
Therefore, using control break logic, DB2 can return distinct DEPTNO, LASTNAME combinations without sorting.
因此使用控制断开逻辑,DB2 可以返回不同的 DEPTNO、LASTNAME 组合,而无需 排序。
Example 16: Collect catalog statistics on table, with distribution statistics on columns deptno and deptname.
示例16:收集表上的目录统计信息,包含列deptno和deptname上的分布统计信息。
Our index is in DEPTNO order, and within that order, in groups of identical (but unordered) values of LASTNAME.
我们的索引是 DEPTNO 顺序的,而在该顺序中,相等(但无序)的 LASTNAME 值分为一个小组。
We can match on one column, and if we use the index the traditional way, the data will come back in DEPTNO order.
我们可以在一列上进行匹配,如果我们以传统方式使用索引,数据将按DEPTNO顺序返回。
The WORKDEPT field of the EMPLOYEE table obviously pointed to the DEPARTMENT table, using the DEPTNO field to link to.
EMPLOYEE 表的 WORKDEPT 字段显然指向 DEPARTMENT 表,使用 DEPTNO 字段可以链接到该表。
Distribution statistics limits are set individually for the deptname column, while deptno column USES a common default.
单独为deptname列设置分布统计信息的范围,而deptno列使用公共的默认值。
Columns in the existing indexes: If an index already exists on EMPNO or DEPTNO, it might not be wise to create another index on the combination.
现有索引中的列:如果在EMPNO或DEPTNO上已经有了一个索引,那么创建另一个关于该组合的索引也许并不明智。
Example 12: Collect catalog statistics on only the table, with basic column statistics for deptno and deptname and distribution statistics on mgrno and admrdept.
示例12:只收集表上的目录统计信息,包含deptno和deptname上的基本列统计信息以及mgrno和admrdept上的分布统计信息。
And DEPTNO should be listed second, allowing DB2 to do a direct index lookup on the first column (EMPNO) and then a scan on the second (DEPTNO) for the greater-than.
然后列出DEPTNO,从而允许DB 2对第一列(EMPNO)执行直接索引查找,然后针对大于号扫描第二列(DEPTNO)。
The runtime will determine the parameters to an SQL operation (such as the deptno in the example) and also analyze metadata of the SQL resultset to create the right XML output types.
运行时将确定一个SQL操作的参数(比如本例中的deptno)并且还分析该SQL结果集的元数据,以创建正确的XML输出类型。
Furthermore, if indexes already exist for both columns (one for EMPNO and one for DEPTNO), DB2 can use them both to satisfy this query so creating another index might not be necessary.
而且,如果已经存在关于这两列的索引(一个关于EMPNO,一个关于DEPTNO),DB 2可以使用它们来满足该查询,因此创建另一个索引也许是没有必要的。