星型模式设计中的维表类型是什么? [英] What are the types of dimension tables in star schema design?

问题描述

在阅读有关星型架构设计的文章时，我发现许多人为不同类型的维度表使用了不同的名称.

When reading about star schema design I have seen that many people uses various names for different types of dimension tables.

请列出每种类型的名称和简短说明.如果有的话，还有一个别名.

Please list the names and a small description of each type. If any list also an alias name.

推荐答案

到目前为止，我已经遇到过以下类型的维度表:

I have come across these types of dimension tables so far:

常规尺寸
标准星形尺寸.

Regular dimension
Standard star dimension.

时间维度
标准星标尺寸的特例.

Time Dimension
A special case of the standard star dimension.

父子维度
用于建模层次结构，FX BOM(物料清单).

Parent-child dimension
Used to model hierarchical structures, fx BOM (bill of materials).

雪花尺寸
也可以用于建模层次结构.

Snowflake dimension
Can also be used to model hierarchical structures.

退化尺寸
将维度属性存储为事实表的一部分时，而不是在单独的维度表中存储时.通常用于诸如交易号"之类的高基数维度.

Degenerate dimensions
When the dimension attribute is stored as part of fact table, and not in a separate dimension table. Typically used for high cardinality dimensions like "transaction number".

垃圾尺寸
具有不同和不相关属性的组合的单个表，以避免在事实表中具有大量外键.通常创建垃圾尺寸来管理快速更改尺寸"创建的外键.通常用于低基数，不相关的维度，例如性别或其他布尔值.

Junk dimension
A single table with a combination of different and unrelated attributes to avoid having a large number of foreign keys in the fact table. Junk dimensions are often created to manage the foreign keys created by Rapidly Changing Dimensions. Typically used for low cardinality, non-related dimensions like gender or other booleans.

角色扮演维度
例如，日期"维度可用于销售日期"，交货日期"或雇用日期".

Role playing dimensions
For instance, a "Date" dimension can be used for "Date of Sale", as well as "Date of Delivery", or "Date of Hire".

最小尺寸
用于快速改变大尺寸.通常用于管理维度中的高频，低基数变化.

Mini dimensions
For rapidly changing large dimensions. Typically used for managing high frequency, low cardinality change in a dimension.

一致的尺寸
在多个数据库表中实现，每个表中使用相同的结构，属性，域值，定义和概念.也可以在共享的维度"名称下看到.

Conformed dimensions
Implemented in multiple database tables using the same structure, attributes, domain values, definitions and concepts in each implementation. Also seen under the name Shared dimension.

怪物维度
尺寸很大.

Monster Dimension
A very large dimension.

缩小的维度
是维度属性的子集，适用于更高级别的摘要.例如，月份"维将是日期"维的缩小维.可以将月份"维连接到其谷物处于每月级别的预测事实表. 尺寸.

Shrunk dimension
Is a subset of a dimension’s attributes that apply to a higher level of summary. For example, a Month dimension would be a shrunken dimension of the Date dimension. The Month dimension could be connected to a forecast fact table whose grain is at the monthly level. Dimension.

推断尺寸
在加载事实记录时，维度记录可能尚未准备好.一种解决方案是为所有其他属性生成具有Null的代理键.从技术上讲，这应该称为推断成员，但通常称为推断维.

Inferred Dimensions
While loading fact records, a dimension record may not yet be ready. One solution is to generate an surrogate key with Null for all the other attributes. This should technically be called an inferred member, but is often called an inferred dimension.

静态尺寸
它不是从原始数据源中提取的，而是在数据仓库的上下文中创建的.可以手动加载静态维度(例如，使用状态代码)，也可以通过诸如日期或时间维度之类的过程来生成静态维度.

Static Dimension
It not extracted from the original data source, but are created within the context of the data warehouse. A static dimension can be loaded manually — for example with Status codes — or it can be generated by a procedure, such as a Date or Time dimension.

多值维度
仅仅是涉及多对多关系的实体之间的桥梁表.多对多也有可能在事实和维度之间.

Multi value Dimension
Is simply a bridge table between the entities involved in the many-to-many relationship. It is also possible that the many-to-many is between a fact and dimension.

然后有一组维度表，我将其称为动态维度. 这些可以进一步分为2组.

Then there is a group of dimension tables I will call Dynamic dimensions. These can be further divided into 2 groups.

尺寸变化缓慢/尺寸变化迅速
随时间变化的维度的属性

Slowly changing dimension/Rapidly changing dimension
Attributes of a dimension that would undergo changes over time

尺寸缓慢增长/尺寸快速增长
与维度中记录/元素的增长有关.

NB:然后可以将它们与尺寸表的大小结合起来，从而产生快速更改怪物尺寸"，缓慢更改迷你尺寸"等.

Slowly Growing Dimension/Rapidly Growing Dimension
Relates to the growth of records/elements in the dimension.

NB: These can then be combined with the size of the dimension table, resulting in "Rapidly Changing Monster Dimension", "Slowly changing mini dimension" etc.

特殊情况:
我不确定这些内容，因此请提供描述/使用方案的帮助.

Special cases:
I'm not sure about these ones, so please help with a description/use scenario.

数据挖掘维度
虚拟尺寸
人口统计维度
启用写入的尺寸
相关尺寸
独立尺寸
主要尺寸
次级尺寸
三次尺寸
信息维度
尺寸分类尺寸
总帐

Data Mining Dimensions
Virtual dimension
Demographic Dimensions
Write-Enabled Dimensions
Dependent Dimensions
Independent Dimensions
Primary Dimensions
Secondary Dimensions
Tertiary Dimensions
Informational dimension
Dimension triage dimension
Non-conforming dimensions from the general ledger

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