ITPub博客

首页 > Linux操作系统 > Linux操作系统 > Kimball Method Slowly Changing Dimension

Kimball Method Slowly Changing Dimension

原创 Linux操作系统 作者:italucia 时间:2011-06-09 16:41:10 0 删除 编辑

The Slowly Changing Dimension Transformation could be in use in  SSIS for the ETL process . SSIS

coordinates the updating and inserting of records in data warehouse dimension tables. For example, you can use this transformation to configure the transformation outputs that insert and update records in the DimProduct table of the AdventureWorksDW2008R2 OLAP database with data from the Production.Products table in the AdventureWorks2008R2 OLTP database. However, since it has the mechanism of each single row comparison and accordingly update row by row, the speed is very slow when it process a very large dimension table with huge number of records. Therefore the open-source plug in 'Kimball Slowly Changing Dimension'could be used to raise up the performance, along with some valuable functionalities.

Two main types of SCD in use.

SCD Mapping:

SCD 1 :  插入新的维度。可选择用已改变的维度的值覆盖原有的值。

SCD2: 插入新增的维度和改动的维度的值。创建一个有效的数据范围以跟踪数据改动。

SCD2举例:Dimension Customer中有两列Start_Date, End_Date.

Customer Example1, 含有列Name, City, Address, Phone NO.,Start_Date, End_Date.

Wang, Beijing,GuangHua Road,123456, 1753-01-01,9999-12-31

当这个Customer电话号码从123456更新到654321时,我们插入新的一行:

Wang, Beijing,GuangHua Road,654321, 2011-06-09,9999-12-31

并将原来的一行更新为

Wang, Beijing,GuangHua Road,123456, 1753-01-01,9999-12-31

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/12374161/viewspace-697514/,如需转载,请注明出处,否则将追究法律责任。

上一篇: Binary Data Type
请登录后发表评论 登录
全部评论

注册时间:2009-05-08

  • 博文量
    28
  • 访问量
    27960