數(shù)據(jù)挖掘復習大綱答案新新(編輯修改稿)
2025-07-16 23:27 本頁面
【文章內(nèi)容簡介】 念模式，包括事實與維。見pptn DMQL首先包括定義數(shù)據(jù)倉庫和數(shù)據(jù)集市的語言原語，這包括兩種原語定義：一種是立方體定義，一種是維定義q 立方體定義 (事實表)define cube cube_name [dimension_list]: measure_listq 維定義 (維表) define dimension dimension_name as (attribute_or_subdimension_list)q 特殊案例 (共享維表的定義) n 第一次作為維表定義 “cube definition” n 然后：define dimension dimension_name as dimension_name_first_time in cube cube_name_first_time實例：使用DMQL定義星型模式q define cube sales_star [time, item, branch, location]:q dollars_sold = sum(sales_in_dollars), avg_sales = avg(sales_in_dollars), units_sold = count(*)q define dimension time as (time_key, day, day_of_week, month, quarter, year)q define dimension item as (item_key, item_name, brand, type, supplier_type)q define dimension branch as (branch_key, branch_name, branch_type)q define dimension location as (location_key, street, city, province_or_state, country)實例：使用DMQL定義雪花模式define cube sales_snowflake [time, item, branch, location]:dollars_sold = sum(sales_in_dollars), avg_sales = avg(sales_in_dollars), units_sold = count(*)define dimension time as (time_key, day, day_of_week, month
黨政相關相關推薦
鄂ICP備17016276號-1