One of the most important design decisions you face is how to capture hierarchy information in a dimension table.
您所要面对的最重要的设计决策之一，是如何捕获维度表的层次结构信息。
You can choose to have one such dimension table for each standard category, such as subject-description, country, and organization.
可以选择为每个标准类别使用一个这样的维表，例如主题描述、国家和组织。
Dimension table design is an essential part of enabling users to move easily through the data, drilling in and out to see what is going on at different levels.
维度表设计是使得用户轻松跨越数据，实现钻入和钻出，来了解在不同级别将要发生什么的必要部分。
TP supports partitioning a table into data partitions along a single dimension.
TP支持按照一个维将一个表分区成多个数据分区。
日期维度表。
时间维度表。
Table-level predicates typically exist on some dimension tables as well.
表级谓词通常也存在于一些维度表中。
A database option that determines if the application should fully populate the time dimension table when the table is created on first startup.
一个数据库选项，用来决定此应用程序是否应在时间维度表首次启动被创建时完全填充此表。
This implies joins between several dimension tables and the fact table.
这意味着要将几个维表与事实表相联结。
A star join query typically involves a fact table and several dimension tables, with join predicates between the fact table and each dimension table.
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。
Generally speaking, a dimension table should be denormalized and flat, with as many columns as needed.
一般说来，维度表应该被非规范化和扁平化，并根据需要使用大量列。
Assume that there is a LINEITEM fact table on one remote source and a PART dimension table on another.
假设在一个远程数据源上有一个lineitem事实表，在另一个远程数据源上有一个part维表。
A database option that specifies the number of days (starting from the current date) to pre-populate in the date dimension table when it creates it on first startup.
一个数据库选项，用来指定日期维度表在初次启动被创建时预填充的天数(从当前日期开始)。
Using the previous example, an XML column might be used in the dimension table containing product data.
对于上述示例，可以在包含产品数据的维表中使用一个xml列。
Each join reduces the size of the fact table by one-tenth due to selectivity of the table filter on each dimension table.
由于每个维度表过滤的选择度，每次连接都会减少事实表大小的十分之一。
You can define the many-to-one relationships among members within a dimension table as a separate dimension table, forming a hierarchy.
您可以将一个维度表中成员之间多对一的关系定义为一个单独的维度表，从而形成层次结构。
The join between the fact table and any dimension table is an equi-join, which makes a hash join possible.
事实表和任何维度表之间的连接都是等值连接，这使得散列连接成为可能。
Multidimensional - You can roll out data on any dimension in an MDC table.
多维-现在可以转出mdc表中任何维上的数据。
In a bit-vector pushdown, for each push-down, the database server hashes the keys from the dimension table to create a bit vector, which is shipped to the fact table.
在位向量下推中，对于每次下推，数据库服务器通过散列维度表中的键来创建发送至事实表的位向量。
If only a few rows are selected from the dimension table so that only a few keys are pushed down, then rows of the fact table might be reduced proportionally.
如果只有几行从维度行中被选出，这样就只有几个键被下推，然后事实表的行数可能也会相应地减少。
Also note that the keyword categories are stored in the dimension table category, where each category points to its parent category within this table.
还需注意，关键词类别存储在维表CATEGORY中，在这个表中，每个类别指向它的父类别。
The performance improvement depends on the selectivity of the filter on the dimension table from which the join keys are pushed down.
性能的提高取决于连接键被下推时所在维度表的过滤选择度。
When a join is executed that incorporates an index that is selective, any column in the dimension table can be used.
当连接执行时，合并选中的索引，此时维度表中的任何列都可使用。
The third method is to add a field to the dimension table that captures old values.
第三个方法是，在捕获旧值的维度表中增加字段。
Otherwise, a new key value is taken from the sequence and used for both, a new entry in the dimension table and as a foreign key in the fact table.
否则，从序列获取一个新的键值，用它作为维表中新条目的主键和事实表中的外键。
If so, the existing ID is read from the dimension table and used as the foreign key for the new entries in the fact table.
如果是，则从维表中读取已有的ID，并用它作为事实表中新条目的外键。
The number of rows selected from each dimension table is less than the number of rows selected from the fact table after all scan filters are applied.
所有的扫描过滤器都应用后，每个维度表选出的行数少于事实表选出的行数。
The level of a dimension table corresponds to number of links it needs to connect to the central fact table.
维度表的层次与它需要连接到中心事实表的连接数目有关。
A dimension table needs a generalized key as the primary key data; this becomes the foreign key in the fact table.
维度表需要作为主键数据的通用键；这将作为事实表的外键。
As you're designing your dimension table, you need to plan for changing dimensional data.
在设计维度表时，需要计划变更维度数据。
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